To begin building with others, the Build Online button must be pressed in the editor. You are then asked whether you wish to host a lobby or join someone else's. Afterwards, a method of connecting is chosen.
when hosting a lobby, the user is required to set a room name, a player limit, whether joined players may edit or play the level, and whether a password is required. If a password is required, the code will be granted upon the lobby's creation.
when selecting join, a list of lobbies to join is shown. Entries will show the owner's name, profile icon, lobby name, whether the lobby is password protected, and whether users who join may edit the level.
During the level process, players may communicate by pressing T and typing a message.
The owner of a lobby may ban other users by opening the player list.
In 1.8.0, the feature was disabled due to complications during development. It is slated to be readded in a later patch.