The simplest is just to copy the existing setup.
You could just create a second folders somewhere else and do a complete copy of the first server, complete with a second copy of DedicatedServerLauncherXxxx.exe at the top.
Before launching the second one, make sure to change the Server name, and the backup locations so they don’t overwrite, but that’s about it. If you are not going to run both at the same time, they can use the same ports.