Download and enable Vanilla Expanded Framework, this mod has to be allowed on the server to work
https://steamcommunity.com/sharedfiles/filedetails/?id=2023507013
Join the server with the username you want to add factions to
If you didnt have Vanilla Expanded Framework before and it asks you to add factions you can skip the next few steps, if not continue
Open the rimworld options by pressing escape
Click mod options
Then find Vanilla Expanded Framework, this can be hard to find if you have a larger mod list, be aware that the search function doesnt always work
Then click the add factions button
This is what the add factions page looks like, if you dont want to add the faction you dont have to
This is what the default settings are for adding a faction, editing this will change how many settlements will add for each faction
Click spawn and do the same for all factions you want to add
Open the map and you you should now have all the factions