This is often the simplest and most effective way to do so for game jams. Shameless plug, I’m working on a future thing that’ll make stuff like this super easy, but at the moment its not ready.
Simply pipe a user’s input into a console command bp node, first prefixing the input with "open ", and that should be good enough.
You should also include a host button, which launches your map with the “listen” option. If you’re using the console command node to host, and say your map name is for example, Arena, the command would look something like this:
open Arena?listen