Navigate to the folder where chdman is located. The easiest way to do this on Windows is to type cmd in the address bar of the folder window.
A command prompt window will open, and CHDMAN will automatically compress each game one by one.
Compression is entirely lossless; your game data, videos, and music tracks remain perfectly intact.
To reverse the process, create a new Notepad file called chd_to_cue.bat with the following code:
For batch conversion (all .cue files in a folder), you can use a simple script (search for "CHDMAN batch converter").