The text and screenshots below were for connecting to the previous server and aren't strictly necessary.
You can make a new instance of the server by downloading the base files, java, extra mods, and the final server backup.
Alternatively if you just want to pick up where you left off in a single player game and don't want set up a server instance, you can extract the world folderr from the previous final server backup and run it with single player FTB.
Screenshots below for reference.
Duplicate your FTB Infinity Evolved mod pack to make a backup just in case.
Rename the new one to something memorable and unlock it.
Open the folder of the mod pack, browse to the root folder of your minecraft instance (will have folders called "backups", "configs", "mods" etc).
Unzip the "tgg_extras.zip" file and drag the "mods" folder and "config" folder into your minecraft instance. If asked to replace any files, click yes.
When run for the first time you'll be shown a confirmation message from the voltzengine mod, accept it.
Server address: theguysgamin.crafted.pro
Server IP: 126.96.36.199
Server port: 25865 (default)