Starting a new game

When no matches are left what do you do after it to keep your score?

press the writing on right upper corner

The other option is to use the arrows to undo your moves to a point where you can try another tactic to beat the game. You only lose 2 points for each move you take back and you still get points when you make matches after that, in the end you usually wind up w/ more points than you would have if you solved it correctly the first time through.