Game length and the cube apply from the next game.
Each side has 15 checkers. Move all of yours around the board into your home board, then bear them off. The first to bear off all 15 wins.
There are 24 narrow triangles, called points. You play White, the light checkers, and move toward your home board in the bottom right, ending in the tray below it. The dark checkers travel the other way, toward the bottom left.
Tap the dice to roll. Each die is a separate move: move one checker that many points, then a checker (the same one or another) by the other number. Doubles are played four times.
Tap a checker, then one of the glowing places it can go. A checker can't land on a point held by two or more of the other colour.
You must use both dice if you can. If only one can be used, you must use the larger one when possible. If no move is possible, the turn passes.
A single checker on a point is a blot. Land on an opposing blot to hit it: it goes to the bar in the middle. A checker on the bar must come back in on the opponent's home board before any other checker can move.
Once all 15 of your checkers are in your home board, you can bear them off: a 6 takes a checker off the 6 point, a 5 off the 5 point, and so on. A number higher than your highest checker bears off from the highest point.
Winning scores 1 point. If the loser hasn't borne off any checkers, it's a gammon, worth 2. If the loser also still has a checker on the bar or in the winner's home board, it's a backgammon, worth 3.
Turn it on in the ⋯ menu. Before rolling, you may tap the cube to double the stakes. The other side either plays on, and then owns the cube (only they can double next), or gives up and loses the current stakes. In a match, the game right after someone reaches one point from winning is played without the cube.
The ⋯ menu also has undo, the opponent, difficulty, match length and pip counts. The first roll of a game is one die each: the higher die moves first, using both numbers.