Reskate server
The dedicated server is a headless lobby. It does not need the game installed and it does not need Steam. Get the archive from the latest GitHub release, not from this site.
How do you run it on Windows?
The Windows server program is in the server archive of each release. Setup, ReSkateServer.json, admin commands, votes, and the anti-cheat checks are in the server readme. The main README points at the same file from its dedicated server section.
How do you run it on Linux?
Each release also ships a native x86_64 Linux server. It does not use Wine and it does not need the game. The README's short setup is: unpack the Linux server archive, run setup-linux-server-libs.sh, then run the server binary. The first run writes ReSkateServer.json. Edit the name and admins, then restart.
Port numbers, Steam library files, and systemd are in the Linux server readme. This page does not repeat numbers that the main README does not list. Open the latest release for the current archive name.