Choosing Your Server Software
The Software tab gives you two options: Public (Stable) and Experimental. Stable is the recommended branch for most servers — it's the well-tested release. Experimental tracks Factorio's in-development builds, which can include new features but also new bugs; use it only if you specifically want to test upcoming changes. Switching branches requires a server restart, which the dashboard will confirm before applying.
Good to Know
Factorio is installed on Spawnly as a standalone headless binary rather than through SteamCMD, which is why you won't find a Steam Workshop browser on the Mods tab for this game — it simply isn't how Factorio distributes mods. Since there's no dedicated World or Properties tab for Factorio either, your save files and any settings files live in the File Manager.
Next steps
For a full walkthrough of adding mods, see Installing Mods on Factorio. Once your world is running the way you want, set up Managing Backups & Restoring Your Server so your save is protected. If you haven't created a server yet, start with Getting Started: Creating Your First Server.