I want to play some Co-Op with a friend but I can't figure out how to set it up

I see no option to host a game anywhere in Zandronum or Zdoom :(

Am I blind here maybe? Anyway, what I want to do is just host Ultimate Doom so the two of us can play through it. Is there some obvious thing I'm missing for doing this?

You need to use doomseeker it should come with zandronum if not download it here. Also are you playing over the internet or over a LAN?

internet.

its frustrating me so much :(

I am using doomseeker now but he cant find my server

Read this and do what it says

EDIT:
Asked a question that already got answered. :P