In a movie "Moana", there's this conversation between Moana and her gramma Tala:
Moana: It's time to put my stone on the mountain.
Tala: Okay! Well, then head on back! Put that stone up there.
Here, what does "head on back" mean?
I guess "head" here means "go". Then, can you say "go on back" instead of "head on back" here?
EDIT
For more context, here's a clip starting with the conversation above.
Best Answer
Your assumptions are correct - head can be treated as a verb, meaning to move in a specified direction. For example.
... and to head on in this context simply means to continue on.
From that, we get head on back. Although it seems counterintuitive (and it is), head on back has become an idiomatic expression meaning to turn around and go back the way you came, or to some previous waypoint on your route.
Go on back could also be used in your example:
It seems equally counterintuitive, but is also commonly used in this context.