please i rlly wanna know

What mod would you like to install?

if you're looking to add it to your server, you go to the files tab, click resources, click client, and put the mod in there. If its a car mod, all you have to do is restart the server. If its a map mod, once its in the client folder, you go to settings and the modded map should now be an option. You click it, then save, and restart your server.