Just a few tips:
First, go
here to fill out a Ban Request.
Second, fill out all the information in the form. Steam ID can be found
here so long as you have the URL of their Steam profile. You can also just type status in console, look for their Steam name and copy/paste the Steam ID from there, but they need to be playing on the server at that moment for it to work. As for their Catalyst Gaming forum profile, go
here and plug in the Steam ID you found earlier. That will take you directly to their CG profile, whose URL you need to copy and paste into the Ban Request.
Third, get actual evidence. Legitimate evidence is in the form of screenshots, rendered videos, and sometimes demo files. Copied and pasted text from console can easily be tampered with and witness testimony can be perjured, so neither are accepted here.