I don't know where to go next! What should I do?

On the bottom screen of your 3DS, Rotom will give you a reminder of your next step every time your current objective changes or you load the game, and you can prompt Rotom to remind you where you're supposed to go by tapping the yellow face that displays your position on the map.

By tapping the map on the bottom screen anywhere but on the current position marker, you can open and view a full map of Alola, which displays a purple flag marker over your next destination.