No automated mod manager
Insurgency: Sandstorm doesn't have a Mods tab with a workshop browser on Spawnly. There's no in-app installer reading from a Workshop content folder the way there is for games like Squad or Unturned.
Be honest about the gap
There's currently no verified, dedicated-server mod-installation path for Sandstorm on this platform. The File Manager (Files tab) gives you access to your server's files, but without a confirmed mod loader or launch flag, uploading files there isn't a documented way to get a mod running — treat it as advanced, unverified experimentation rather than a supported procedure.
Good to know: Game.ini
Sandstorm's server automatically generates a config file at Insurgency/Saved/Config/LinuxServer/Game.ini on first boot. It doesn't cover mods, but it's where server-side settings like max players, RCON access, and map-voting behavior live — worth knowing about even if you never touch mods. Edit it through the File Manager, save, and restart to apply changes.
Next steps
For branch selection and general setup, see Getting Started with Your Insurgency: Sandstorm Server. Back up before making config changes — Managing Backups & Restoring Your Server.