Do you want to/ know how to open ports on your router?
Easiest way (but not the safest way) -
open the port for the server on your router. 5520 is the default hytale port. If you do not know how then google your router + port forwarding.
Go to ipchicken.com and get your external IP address.
Tell your friends to connect to your ip address:port number
example 66.249.68.36:5520
playit.gg has a setup that will connect players to your server without port forwarding. Here is a video I found explaining it. https://youtu.be/1rRe3_gQqus?t=679