Stockfish is an engine. You need to use it in a program designed to use it. The stockfish site gives you its latest version and a choice of downloads.
A program that runs engines is called a GUI, which stands for something like graphical user interface. A good free one is called Arena.
You can read a lot more about GUI and UCI at:
http://computer-chess.org/doku.php
Thanks, but the file is a WinRAR thingy. What does that mean?
Winrar files are just compressed files. Go to the stockfish website and get the current version for Windows (or Linux or whatever you are running.)
They also tell you what to do to get it working, which is basically:
Yeah, a .rar file extension means that you didn't get the engine from the official Stockfish site. (The official site offers zip files.) It's generally a bad idea to get freeware from secondary sources, because you never know if someone has added malware to the download.
Here's the link for the official Stockfish download:
https://stockfishchess.org/download/
Thanks, I downloaded Arena, but how do I "tell" it where my Stockfish files are? Please help.
By the way, is it okay if the stockfish files are in zip format? will arena be able to access them?
I may not be able to reply immediately to an answer you give me, but I'll be grateful for advice. Thanks anyway.
Thanks, I downloaded Arena, but how do I "tell" it where my Stockfish files are? Please help.
Simple "big picture" instructions:
1) Put the Stockfish "zipped" file in a separate folder, then unzip the file. (Let me know if you need instructions to do that.)
2) Open up Arena, then in the menu, go to "Engines --> Install New Engine..."
3) Navigate to your opened Stockfish zip file, and select the proper Stockfish executable file. This will be a Stockfish file with an .exe file extension. There will be several files to choose from, and depending on your hardware, one or two of them might not work. If you pick the wrong one, it will crash when you try to install it. If that happens, try another one.
4) If Arena asks whether the engine is UCI or Winboard, answer "UCI".
5) Once the engine is installed, you might need to configure the engine parameters (settings). There are a couple of ways to do this. One way is to use the menus ("Engines --> Engine 1 --> Configure"). Another way is to right-click your mouse cursor in the engine analysis window at the bottom, then choose "Configure Stockfish".
By the way, is it okay if the stockfish files are in zip format? will arena be able to access them?
Nope, you have to unzip the files for Arena to see them.
Regarding UCI, there are three main engine protocols these days: UCI, Winboard, and the proprietary ChessBase protocol (ChessBase engines have a .eng file extension). UCI stands for "Universal Chess Interface". Most engines are UCI, but there are still some Winboard engines out there. Stockfish is a UCI engine.
Here's a short video of the process of installing and configuring a UCI engine in Arena.
https://1drv.ms/v/s!AgVhuW8u-GbEgRfAnyQD8uzxGnVs
Here's a short video of the process of installing and configuring a UCI engine in Arena.
Looks quite complicated.
Here's a short video of the process of installing and configuring a UCI engine in Arena.
Looks quite complicated.
It gets a bit easier after you've done it a few thousand times. 
Here's a short video of the process of installing and configuring a UCI engine in Arena.
Looks quite complicated.
The video shows both installation and configuration. It's really not difficult but there's a small learning curve if you're not familiar with the process.
Here's a short video of the process of installing and configuring a UCI engine in Arena.
Looks quite complicated.
The video shows both installation and configuration. It's really not difficult but there's a small learning curve if you're not familiar with the process.
You didn't get the sarcasm.
Here's a short video of the process of installing and configuring a UCI engine in Arena.
Looks quite complicated.
The video shows both installation and configuration. It's really not difficult but there's a small learning curve if you're not familiar with the process.
You didn't get the sarcasm.
I didn't detect it either. Sarcasm isn't easy to convey in print. I wonder if V3 might have some kind of sarcasm emoji thingy? (Although I'm not yet on V3.)
Is Fritz 15 a good GUI? Arena seems a little hard to use.
Plus, can I load Stockfish and komodo onto Fritz? If not, suggest a GUI (other than Arena) with which I can use Stockfish and Komodo. It is okay even if it is an older version of Fritz.
Is Fritz 15 a good GUI? Arena seems a little hard to use.
Plus, can I load Stockfish and komodo onto Fritz? If not, suggest a GUI (other than Arena) with which I can use Stockfish and Komodo. It is okay even if it is an older version of Fritz.
Arena is free and is not very complicated.
If you bought Fritz, good for you. I doubt it is any easier than Arena. People are always coming here because they have difficulty with Fritz.
Is Fritz 15 a good GUI? Arena seems a little hard to use.
Plus, can I load Stockfish and komodo onto Fritz? If not, suggest a GUI (other than Arena) with which I can use Stockfish and Komodo. It is okay even if it is an older version of Fritz.
The last Fritz GUI that I bought was Fritz 8, so I'm a little behind the times regarding Fritz. Fritz is generally a good GUI, but as notmtwain mentioned, I doubt that Fritz is any easier to use than Arena.
Since the Fritz GUI should accept any UCI engine, you should be able to install Stockfish and Komodo into the Fritz GUI.
Is Fritz 15 a good GUI? Arena seems a little hard to use.
Plus, can I load Stockfish and komodo onto Fritz? If not, suggest a GUI (other than Arena) with which I can use Stockfish and Komodo. It is okay even if it is an older version of Fritz.
Yes you can, you can install any UCI engine into Fritz. I have installed Stockfish and Houdini into my old version of Fritz (version 10).
I,ve been trying to download stockfish but it has been turning up as a WinRAR file. How do I use the actual program? plus, they insist on som UCI thing which I don't understand. Help.