Chess engines are the brains of any chess program. Most modern engines come as separate entities to be added to your favorite GUI (Graphical User Interface). This post is aimed at helping you get some free chess engines and prepare them to install in your favorite GUI. I'll cover the GUI installation in separate posts.
How do you know what engines are the best?
Here is a list of the top rated engines. http://www.computerchess.org.uk/ccrl/4040/
Where can I get these engines? Well you can Google them by name. "Komodo Chess Engine" for example. Just Google "Komodo" and you'll get a lot of links to the lizard.
Below are links to the current top three free engines. After you download them. You will need to unzip them. I recommend keeping them in their own folder. First I would make a folder called chess engines somewhere easy to find. Because you may want to use these engines in more than one program. Example c:\chess engines\Fire5
Komodo https://komodochess.com/
Stockfish https://stockfishchess.org/
Fire https://chesslogik.wixsite.com/fire
The engines will often come in 32 bit and 64 bit versions. They may have both versions inside the zipped file. If you have to select at the time of download you need to know which kind of computer you have. This is how you can tell https://www.computerhope.com/issues/ch001121.htm.
So there may be a x32 (32 bit) version a x64 (64 bit) version. Also you may see bmi2 and popcnt versions. These additional versions are compiled to take advantage of special features built into specific microprocessors. The speed gained by running these versions are small but feel free to try them. If they don't run just switch back to the plain version. The BMI version may require changing settings in your computer bios. If you you want to do that here is a thread on that topic. http://www.chess2u.com/t10505-bmi2-or-popcnt
All about chess engines. https://en.wikipedia.org/wiki/Chess_engine
More Chess Engine Info and download links. https://www.chessengeria.eu/