How do I get Stockfish? I suppose where is a web site I can download it from...
Fritz 13,14
The Stockfish website says I will need to use my own UCI-compatible chess program. What does that mean?
The Stockfish website says I will need to use my own UCI-compatible chess program. What does that mean?
That seems a little technical to be warning people heh. All engines / interfaces you're likely to find (or be interested in) are UCI compatible.
What it should tell people is there are essentially two things you need. An interface (which is basically just menus, buttons, a board, all that graphic stuff) called a GUI. You can download one for free like Arena. (If you buy something like Fritz, then you don't need to download anything. It's an interface and and engine.) This link may help, also you can download a GUI off this site.
http://www.playwitharena.com/?Welcome_to_Arena
The second thing you need is an engine. The engine is the program that calculates moves in a chess position, gives an evaluation (like +1 or mate in 3). But without an interface (GUI) you can't really interact with it.
https://stockfishchess.org/download/
Or google any free / open source engine on this list:
http://www.computerchess.org.uk/ccrl/4040/

Try ChessX, Arena and Scid vs PC for free if you have a PC and see which one you like best. It will take you about a week to decide. Chessbase has a very large database of over 6,000,000 games you can search through to find whatever you want to look at in chess. The largest free database I have found is the 2.2 Megabase. A GUI supports a chess engine you can use to evaluate positions. So you guess a move and see what the engine thinks of your idea. I have Fritz 7 and like it. But it doesn't work like a database and it's oh so yesteryear.
I've just downloaded Arena GUI from it's website few minutes ago. Everything looks fine, there is an icon on the desktop, and I was able to open it without a problem. I will try to download Stockfish too in a few minutes. Assuming that everything is fine with Stockfish, how do I put two of them together?

I believe you download Stockfish, install it, then when you open it Arena might recognize it. If that's not right you'll have to do a Google search and you'll find Chess.com posts about it.

I've just downloaded Arena GUI from it's website few minutes ago. Everything looks fine, there is an icon on the desktop, and I was able to open it without a problem. I will try to download Stockfish too in a few minutes. Assuming that everything is fine with Stockfish, how do I put two of them together?
Here's a short video where a chess engine (Komodo) is installed in Arena.
Look here ---->> Using Arena

Lucas Chess is a very good free gui. It has stockfish as well as 30 other engines already installed so you can experiment with different engines and decide which one you like.

Here's a short video where a chess engine (Komodo) is installed in Arena.
Look here ---->> Using Arena
Very good, may I ask what software you used to record the video?
I'm not sure whether my computer is 64 - or 32- bit. It's DELL Latitude E6400 laptop. Do you have any idea? I got it from somebody else (it wasn't brand new). I'll double check the user manual but do you know off the top of your head which one it is?
While we are on the subject of chess engines... How do I use all that information provided by the engine when I analyze a position. I tried to analyze a position from Arena using it's own default engine (I think it's SOS something...) and clicked on "Analyze Now" and the screen on the bottom started showing lines of variations starting with different initial moves and it kept running for several minutes until I stopped it manually...

Here's a short video where a chess engine (Komodo) is installed in Arena.
Look here ---->> Using Arena
Very good, may I ask what software you used to record the video?
A freebie called srecorder ---->> http://srecorder.com/
If you need help, please contact our Help and Support team.
I've just looked at the chess.com online store and what kind of software they have. I'm kind of new to this computer chess technology. They have Fritz 13, 14 software. What is a chess engine and what else does this software have? They say the package includes 6-month membership in ChessBase (?) web site. Why is that?