Level selection system

How may i add a level selection system to a multiplayer game in which it’s user can choose to host a game with his/her map of choice and game type? Would i need a gui page to do so? If so then feel free to move this thread to GUI topics. I was just in rut because i want my users to be able to host a game of their choice and map i have design of their liking. If i were to do this could i make it all in one unity project scene? like have each map in the general grid and it just loads certain sections? OR would each need to have a scene on it’s own?
Thank you!

I think the GUI and scene of its own would work best, but i dont know how to do networking stuff yet, though.