I’m a ten year old boy and need advice please



I would train tactics, puzzle rush is a good way to do it because of the competitive element. At your level it's quite common to hang pieces so take advantage of that and avoid it yourself.
Openings aren't that big of a concern at your level, a fun way to study them is to play daily chess and use the database to follow particularly long openings and see the options in an intuitive way.
"... for those that want to be as good as they can be, they'll have to work hard.
Play opponents who are better than you … . Learn basic endgames. Create a simple opening repertoire (understanding the moves are far more important than memorizing them). Study tactics. And pick up tons of patterns. That’s the drumbeat of success. ..." - IM Jeremy Silman (December 27, 2018)
https://www.chess.com/article/view/little-things-that-help-your-game
https://www.chess.com/article/view/how-to-start-out-in-chess
https://www.chess.com/news/view/a-new-years-resolution-improve-your-chess-with-new-lessons
"... In order to maximize the benefits of [theory and practice], these two should be approached in a balanced manner. ... Play as many slow games (60 5 or preferably slower) as possible, ... The other side of improvement is theory. ... This can be reading books, taking lessons, watching videos, doing problems on software, etc. ..." - NM Dan Heisman (2002)
https://web.archive.org/web/20140627084053/http://www.chesscafe.com/text/heisman19.pdf
"... If it’s instruction, you look for an author that addresses players at your level (buying something that’s too advanced won’t help you at all). This means that a classic book that is revered by many people might not be useful for you. ..." - IM Jeremy Silman (2015)
https://www.chess.com/article/view/the-best-chess-books-ever
Here are some reading possibilities that I often mention:
Simple Attacking Plans by Fred Wilson (2012)
https://web.archive.org/web/20140708090402/http://www.chesscafe.com/text/review874.pdf
http://dev.jeremysilman.com/shop/pc/Simple-Attacking-Plans-77p3731.htm
Logical Chess: Move by Move by Irving Chernev (1957)
https://web.archive.org/web/20140708104437/http://www.chesscafe.com/text/logichess.pdf
The Most Instructive Games of Chess Ever Played by Irving Chernev (1965)
https://chessbookreviews.wordpress.com/tag/most-instructive-games-of-chess-ever-played/
Winning Chess by Irving Chernev and Fred Reinfeld (1948)
https://web.archive.org/web/20140708093415/http://www.chesscafe.com/text/review919.pdf
Back to Basics: Tactics by Dan Heisman (2007)
https://web.archive.org/web/20140708233537/http://www.chesscafe.com/text/review585.pdf
https://www.chess.com/article/view/book-review-back-to-basics-tactics
https://static1.squarespace.com/static/5856bd64ff7c50433c3803db/t/5895fc0ca5790af7895297e4/1486224396755/btbtactics2excerpt.pdf
Discovering Chess Openings by GM John Emms (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
Openings for Amateurs by Pete Tamburro (2014)
http://kenilworthian.blogspot.com/2014/05/review-of-pete-tamburros-openings-for.html
https://chessbookreviews.wordpress.com/tag/openings-for-amateurs/
https://www.mongoosepress.com/catalog/excerpts/openings_amateurs.pdf
Chess Endgames for Kids by Karsten Müller (2015)
https://chessbookreviews.wordpress.com/tag/chess-endgames-for-kids/
http://www.gambitbooks.com/pdfs/Chess_Endgames_for_Kids.pdf
A Guide to Chess Improvement by Dan Heisman (2010)
https://web.archive.org/web/20140708105628/http://www.chesscafe.com/text/review781.pdf
Studying Chess Made Easy by Andrew Soltis (2009)
https://web.archive.org/web/20140708090448/http://www.chesscafe.com/text/review750.pdf
Seirawan stuff:
http://seagaard.dk/review/eng/bo_beginner/ev_winning_chess.asp?KATID=BO&ID=BO-Beginner
http://www.nystar.com/tamarkin/review1.htm
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
https://www.chess.com/article/view/book-review-winning-chess-endings
https://web.archive.org/web/20140708092617/http://www.chesscafe.com/text/review560.pdf

chesstempo.com for tactics
chess.com for games/practice
If you have premium use chess.com opening explorer and learn one main opening for white, one for black. Else, you can get the Encyclopaedia of Chess Openings. There are 5 books, you can choose which ones you want, since each covers different openings.
Dvoretsky's Endgame Manuel is best endgame book.
Has there been an ECO revision since 2010?
https://web.archive.org/web/20140627063241/http://www.chesscafe.com/text/hansen145.pdf
"... For new players, I cannot recommend books that use [an encyclopedic] type of presentation [of opening theory], because the explanatory prose that elaborates typical plans and ideas is usually absent, thus leaving the student without any clear idea why certain moves are played or even preferred over other apparently equivalent moves. ..." - FM Carsten Hansen (2010)
The table at
https://www.chess.com/forum/view/general/modern-chess-openings-tables
is (I think) not an actual ECO table, but I think it gives some idea of what it is like to try to use ECO information.
"... For inexperienced players, I think the model that bases opening discussions on more or less complete games that are fully annotated, though with a main focus on the opening and early middlegame, is the ideal. ..." - FM Carsten Hansen (2010)

Keep it very simple. Here's a good simple plan : study basic endings until u know them thoroughly. Do tactics every day but don't get rediculous and get burned out by doing too many. 10 a day is good... even 5 will do, but learn the ideas behind them. That's the important part, the ideas. Get a book explaining them. Play slow games so u have time to think and calculate accurately. Not much blitz, definitely no bullet while ur getting ready for a tournament. Play in slow otb tournaments and spend a lot of time analysing the game without a computer, preferably with someone at least 500 points better than u. If u want to learn openings the very best way is to learn the pawn structures first. Pawn structure training will give u a road map and a plan for not only the opening but right through the middle game to the ending. If u learn pawn structures well ur gonna be a beast of the chess board very fast.
There, it's that easy. Have fun.
Good advice here.
"... before discussing the specifics of Dvoretsky's Endgame Manual [henceforth 'DEM'], a word of warning is in order. I must emphasize that this is a terribly advanced work that I don't think is a very good way for the average player to study the endgame. The majority of the examples are complex and position-specific, and neither the average student nor even strong masters will follow or play over most of the hundreds of positions that are given extensive analysis, not to mention the subvariations derived from those positions. Even when introducing 'the basics', Dvoretsky's approach is often more complex than is necessary for an average student, and in any case such a thick book will seldom be used for the sake of elementary instruction. The majority of the other material is frankly very difficult. So take note: I don't want to be blamed, in praising this book, for your purchasing something that you find intimidating, relatively dull, or otherwise unsatisfying. That said, if you are up to a real challenge and have a great deal of time to devote to reading and playing over examples you will inevitably derive great value from this work. ..." - IM John Watson (2005)
http://theweekinchess.com/john-watson-reviews/the-end-game-comes-before-we-know-it
http://www.jeremysilman.com/shop/pc/Dvoretskys-Endgame-Manual-3rd-Edition-78p3502.htm
https://web.archive.org/web/20140708233815/http://www.chesscafe.com/text/review399.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/2703.pdf
"... I'm convinced that Silman's [Complete Endgame Course] will take its place in history as one of the most popular endgame books ever. It has already caught on with the average player in a big way, confirming Silman's status as the king of instructional writers. He writes in a clear and casual style, and time and again has shown the ability to reach those who feel intimidated by the lofty approach that a grandmaster will often take. ... Silman ... defines what he thinks is necessary to know at specific rating levels. For example, the beginner or unrated player needs to know ... Silman's idea is to wait until you climb in strength before you worry about more advanced material. Then, as a Class 'E' player (that's 1000-1199), one must learn ... Silman's book emphasizes to the student that the important thing is to master the strictly limited material at hand, rather than get confused by endings that won't help your results at that level. Perhaps even more importantly, Silman is able to use his teaching experience and talk to his readers in a way that they can handle, in a friendly manner and without condescension. ... I'll also repeat the point that David Ellinger in ChessCafe makes: '[This ...] demonstrates who this book will truly serve best: anybody who coaches chess. For me, as a perpetually near-2000 player who does part-time coaching, I’ve got in my hands a great resource that will have something for every student, no matter the rating.' ..." - IM John Watson (2007)
http://theweekinchess.com/john-watson-reviews/theres-an-end-to-it-all
https://web.archive.org/web/20140708103149/http://www.chesscafe.com/text/review594.pdf
https://www.silmanjamespress.com/shop/chess/silmans-complete-endgame-course/

So what?
Play and study every day.

So what?
Quick learning? I mean, if he is disciplined, he'll be a master in no time (I hope).

How do I get super good at chess and what are good openings and tactics for me?

So what?
..because what would be suitable for an adult may not be suitable for a 10 year old boy. Think about it.

When I was your age, ages ago, I wasn't much of a chess player (not in the conventional sense), so it's a bit strange for me to figure what would work best for a ten year old, so I'll give some general purpose all round fun advice.
Play! Play! Play! - when I started off on this site a few years ago I was rated +900, since then I've played more than a thousand rapid games (most of them 30|0), and now my rapid is rated +1450, though on a good day I could beat a 1900 and give him a rematch and beat him all over again 😁.
Play as many games as you can and learn from each one. Use the analysis tools available and study up on your fundamentals and principles. It'll be even better if you have friends to discuss chess with.
It's always interesting to pull out a line from a book amongst other boys and girls, and see what you can all make of it (chess.com boys and girls included). Good luck.