question about adding mods to server

Well im using xenon servers atm and im trying to install addons to it. steam wont let me make a collections for some reason so they lead me to filezilla. how do i add my addons to filezilla and show up on my server? sorry if newbish question, first time server owner here.

FileZilla is a FTP client, you use it with a provided username and password to remotely access your server files.

WinSCP will also work as well, although the most common one is Filezilla.