I always create a "Browse" Group with functions.
First I have a function like "startBrowsing". I set local variables like on which page I'm currently, what is the maximum page count etc.
I think you should make three variables:
World
Stage
Maximum Stages
Then I have a touch event when my browsing arrows are clicked.
In this event I first check in which direction I'm browsing. When I'm going to the right e.g., I add 1 to my page (or in your case to your stage).
You also need to check some things:
Did you reach maximum stage? -> Then maybe go the the next world
Did you reach minimum stage?-> Then go to the world before
Did you reach absolute minimum/maximum? Set one arrow invisible.