Once you're whitelisted (we will let you know on discord) you'll need to download the modpack.
Our server is running the Feed The Beast Ultimate Anniversary Edition modpack version 1.2.0, which can be downloaded through their website and app, or the FTB modpack browser in our recommended client:MultiMC (download here - Links to MultiMC's download page)
When you have that installed just launch it from MultiMC (first launch will take a while), enter the multiplayer menu and connect to play.saltcraft.xyz and that's it, you're done!
You must be a member of the Discord server to join. All Discord server rules apply. Griefing and building large redstone machines that lag the server are not allowed.