What version of the MedMod are you attempting to install? If its the latest beta, the Readme isn't complete, but if its 2.04 for Vikings or 1.1 for MTW then you can get the readme at his site.

http://wes.apolyton.net/

Re installation, 2.04 and 1.01 are self-install (.exe); the beta is a Zip. Extract the Zip into your Total War directory and allow it to overwrite all files. If I recall correctly the same applies for the .exe files.

On all but the latest beta, you should see a version label on the Main Screen: MM v.X

Good Luck