Hello kind sir!!
First if all if staff did not hop on and deal with it then it means you must follow the template here :
zarpgaming.com/index.php/forum/report-ab...ban-request-template
For evidence of steam id you must open the console and type !status and take a screenshot by pressing f5 ( default ) and linking it to here, for the hacking evidence you must record the hacker ( preferably in both 3rd and 1st person ) and post it on whatever platform that can be reviewed by anyone, now if you do not have a recording software you can use the built-in game recorder, to use that you must goto settings and scroll down a bit and you will see a “start/stop recording a video” and it will be unbinded so you’ll need to bind it to a key of your choice, if it affects your fps lots then you can simply record a demo which should be right above the video bind, then you can use a non-built in recording software and then goto demos on GMOD’s main menu and opening the demo you recorded.
Thanks for reporting players and keeping it clean!