It's simple really, if you read the dang description, firstly, you need the advanced duplicator v2 tool as listed in the description, once you have that then you will need to go to the onedrive link shown in the description, next you will need to take that file and go to the advdupe2 file in your pc, here's the order you go in at least from my pc

"Program files (x86)"
"Steam"
"steamapps"
"common"
"GarrysMod"
"garrysmod"
"data"
"advdupe2"

Then you take the file downloaded from the link and put it in that folder. Hope this helps, and for gods sake read the description first