By default, all you need to do is restart your server. On the restart, the server will check for the latest version and download it.
You can toggle on and off updates on the server Overview page
Satisfactory guide
How to update a Satisfactory server
Quickly update your Satisfactory server with Kinetic Hosting! Simply restart your server—the latest updates will automatically download on restart. Prefer manual control? Toggle auto-updates on or off directly from your server's Overview page!