Answer:
You find me behind the stars; or in a sixth seventh or third. It takes something round a computer and me to make pie. I am bigger than anything you can think of.
You turn me over after you have travelled far.
If you drop me I'm sure to crack. But give me a smile and I'll always smile back.
So simple, that I can only point. Yet I guide men all over the world.
I have leaves on my fruit my fruit is on my leaves.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.