[Question]How to install Add-on/Plugins onto Trouble In Terrorist Town server.

Hello there, I’m new to this forum, and I have a friend who have a TTT server, and he and I was wondering how to install Addons or plugins onto the server, and the server is running ULX User Management.
We’ve never tried to install any addons or plugins before, so we know nothing about it, at least I don’t, so if u have a detail tutorial that would be great, and if u have a video tutorial that would be ever better, thanks!

Each addon should include some basic instructions, since they’ll all differ. Most of them will go into the addons folder, though.