There are two ways to go through the next stage. The "easy" way forces you to do all the tasks in a particular set order, whereas the "challenge" path allows you to choose the order in which you add features to your fledgling game.
Which path do you prefer?
Note that they both end up with the same code in the end.
GOTO 200 if you want to take the straight and easy path
GOTO 101 if you want to take the challenging path