Hosting a lobby and multiplayer functionality

Hello!
I am a solo developer working on a drinking game, so far I have made a lot of progress with the game and it’s main features in the offline game mode, as for the online game mode I am having some issues, I want to let a player create and host a lobby with a code that others can use to join.

If anyone has any recommendations for what I should be doing or looking for feel free to let me know.