I'd recommend using the default server to play with everyone else (this only requires you to install the mod, not set up a server).

If you're certain you want your own server, it can be a little tricky to set up. I am renting a VM on Azure, used SCP to transfer the files, and executed it using SSH. There are probably some tutorials on the internet you can follow for things like Minecraft servers, which may be similar?

If you want to run it locally, you'll just need to launch the server application. You might need to change your firewall settings to allow listening on port 7777. If you're playing with people across the internet (not just a local network) you might also need to set up port forwarding. All of this can be very time-consuming and a bit difficult - it's a bit beyond my scope to help people set this up - I'm not very experienced with this myself. There are some good tutorials out there, but it may be easier if you have a friend familiar with any of this stuff to help talk you through the process.

Sorry it's gotta be so complicated! I don't have the resources to simplify or automate the process for you. Networked games are tricky!