I need help in setting up a server. I'm not good at this stuff.

It's really simple actually.

First off you need to port forward (or you can check if your router supports UPnP, if it does then check that box when hosting a server, if not don't check it.)

Next you want to go onto your router settings, to do this you have to put your router's IP into the address bar, apparently, 192.168.15.1 is the default IP of most VOIP routers, but if you don't know then press the windows and r button, type in "cmd" and then put in the box that pops up "ipconfig/all" a bunch of things should show up, now look for "Default Gateway" and put in the number it shows there, for example mine starts with 192 (Note - they never have letters in them, ignore the ones with letters in them)

Now, since there are different internet provider look for some advanced settings or port forwarding settings, then set the ports for 14242 to be open and make sure the protocol is "UDP"

If you have any struggles on any of these, notify me and I'll try to get back to you.

Another note - If you can't find your settings on your router page for port forwarding, just tell me what type of router and internet provider you have and I might be able to help.

Have fun.

so if I turn the UPnP, do I still need to port forward?

It depends, if your router supports UPnP then you could do that, but I recommend port forwarding, if your router supports UPnP then you could try that, but I personally don't know if it's a good alternative or not, hope I've helped.

And do you recommend some port forwarding program or tutorial?

Looking up a video on it might help, I don't think there are port forwarding programs, but again, search up if your router supports UPnP, if it does you can use that when hosting a server, but I don't know if UPnP works so I'm not sure if it will.