Ah, I see, so the point that the dice doubles belongs to the outcome of one game? Like in a 5 point match, or 11 point match. I see now, thanks for taking the time to explain, I appreciate it! How do you decide who starts with the cube? Is it the person who wins the first throw?
At the start of the game, the doubling cube belongs to neither player, and either can make the first double. Physically, the cube is usually placed on the side of the board, midway between the two players, with the "64" facing up.
Doubling strategy, I might add, is probably the most difficult part of the game.