For convenioence, just use the following modpack on CurseForge, so you have all mods you need to join plus some nice additions to the game.
https://www.curseforge.com/minecraft/modpacks/eleine-legion-fan-server
It comes in 2 versions:
essentials: having the mandatory mods
full set: having everything we love to use on the server
To install, you need CurseForge