I can't start a split-screen game.

To start a split-screen game, please do the following:

1.  Connect the same number of controllers to your Xbox One as the number of people you want to play.
2. On the game's Home screen, press the Menu button of all the controllers that have not yet joined the game.
3. Select the profile you want to use when the select profile screen appears.

After going through those steps, the player or players will be added to the party list on the game's Home screen. A split-screen game will begin when you select a dungeon from a quest.

NB: The following restrictions apply to games played on a guest profile:
- Save data will be a copy of the data on the host profile (the profile used to create the guest profile).
- Tool bags will not be copied.
- Happy Jewels cannot be acquired or used.
- Certain game features will be restricted.
- When the host profile quits the game, the guest players also quit.