Will this support multiplayer as in multiple clients in the same roaming lobby?
If this is just for the owning client you simply create a map that will be your roaming lobby. Then in the main menu you’ll need a button to load that map.
In the roaming map you’ll need to apply UI menu to the controller class. When a selection is made you’ll call Find Session and search for sessions (servers) running that map.
Multiplayer version requires either one of the clients to be a Host (Listen Server) and have all others join the host. Or use a dedicated server that starts with roaming server, clients join it.
When all clients have made a map selection, the GM will tally the vote and load seamless travel to that map.