MULTIPLAYER SESSION ON UNIQUE MAP FOR AKK PLAYERS

Hello Guys i am making a multiplayer game with a unique map where all player can join and Play, i have all the start menu that are “offline”. how i can set up this thing? i was thinking to dedicated server on AWS, but have i to create unique lobby and unique session that when the players click “play”, join automatically or are there other ways to implement this? Thanks to all Guys!