I'm trying all the time, without success, create a CSM mod. Please, can anyone help me or explain me how to do, step by step?

Hi everybody, I am new here and I am really pleased to find so many people loving the best F1 game ever!! I used to play it many many years ago and I am not a nerd, so sorry if I ask basic things that you probably take for grant. In order to have a certain Mod working, am I supposed to...