Failing to understand how to start Popeye I am trying to run the chess solving program Popeye, but I am failing to understand how to start the program on Windows.
There is an English guide, and this is all of what is tells you to do:

Starting popeye:
Change the name of your preferred executable to py.exe
To operate it from the terminal:                py
To solve problems recorded in file XX:          py XX

I'm basically illiterate when it comes to code. Can anyone explain how to start Popeye?
For those interested, you can download the exe from https://sourceforge.net/projects/popeye-chess/

There's no reason to alter the name of the executable.
You have to enter command prompt.  On windows this is done by running cmd.exe, or you can use a dos emulator.
When you're in the folder which contains the popeye.exe file, you can start the program by typing popeye.  However, the program is "dumb" and you need to provide more parameters.  The first parameter is the file which contains the puzzle(s).  There are three other parameters, but they're not needed.

For example, the command "popeye puzzle.pgn" starts the popeye program and tells it to solve the puzzles in the puzzle.pgn file.  The program should produce a generic file with the answer(s) and misc. info about what the program did.

There is another method, but that is more restrictive and not really worth mentioning.

This is the method on a Windows OS.  For Linux, Apple, or other OS the procedure is slightly different, but users of these OSes normally are already familiar with these methods.