Answer to chess lesson problem?

I tried clicking on the first chess lesson, and I have no idea what answer it's looking for. I have made every single legal move on the entire board, as far as I can tell, and the system tells me that every single one of them is incorrect. The hint didn't help. Where can I get the answer to this problem, preferably with an explanation of why it is the answer?

Just off the top of my head, I bet they want you to castle....the Don't Forget Your King is kind of a clue...

Sorry, I literally just started playing, I have no idea what that is; I looked it up, and couldn't make sense of it. Pretty strange choice for the very first chess problems ever given to anybody, LOL!

It's probably to make sure you know all the rules...

Couple of useful links here...Oh and you might want to look up "en passant".  It's a tricky pawn move you need to know...

https://support.chess.com/customer/en/portal/articles/1444795-please-help-me-learn-the-rules-of-chess---i-want-to-learn-how-to-play-

Probably… which I don't, LOL. However, I literally just won my first game against the computer using my own strategy!

Edit: Whoops, you posted while I was posting! Thanks for the link! It's a little more detail than I can absorb right now, but I'm sure it will be useful later.

Those are too confusing too, LOL! I'll just keep playing for now, and hopefully pick it up as I go along.

 And here's the rest of the free courses...Highly recommended to get you off to a good start...

https://www.chess.com/blog/webmaster/free-chess-mentor-courses

Sure, why not?  I mean, how hard can this stuff really be?  

 I can't make heads or tails out of any of these so-called beginners lessons; they throw out all these terms, with no explanation of what they're talking about!

And yes, I know that grand masters are all geniuses, but I know people who are dumb as a stumps who play recreational chess with no problems, and that's all I'm really hoping for.

I can't follow the notation without dragging my fingers all over the screen; I appreciate all the links, but they're all using notation right from the beginning, and I just don't have that kind of spatial relations. Meanwhile, the computer keeps telling me that every move I make is inaccurate or a blunder, but I keep getting it into stalemate or checkmate, LOL

I did try to start from the very beginning. Some of the rules are confusing, and the notation makes no sense at all. Fortunately, it turns out to be totally possible to play without either knowing the notation or most of the rules.