Force client downloads from my server?

I need it so if someone joins in they download the files they need like player models.

in the server CFG (assuming there is one, I haven’t hosted a server before) add the following line:
sv_downloadurl “%%%%”
Replace %%%% with the path to the folder on your server that mimics the Gmod root folder (the one with the models, materials, maps, etc. folders),1037.msg16116.html#new

There’s a detailed tutorial regarding doing this kind of stuff.

Gasp you guys are the shit