Guides for every server

These work the same whichever game you run.

Connect to your server with SFTP Upload big worlds and mod folders with an SFTP client instead of the browser. Where to find the address, and which password to use.
Download a copy of your world Keep your own copy of your save. How to archive a world in the panel and download it safely, even when it is several gigabytes.
Let your friends help run your server Give friends the console and the files without sharing your login, using sub-users and the permissions you choose.