Tree Behaviour Help

Just starting with the tree behaviour to create a simple dynamic navigation.

 

So I added the cookbook steps to give me my:

 

My Categories

• Fun
  • Sport
    • Surfing
    • Extreme knitting
  • Friends
    • Gerald
    • Gwendolyn
• Work
  • Reports
    • Annual
    • Status
  • Trips
    • National
    • International

So i go to add but form is empty. How do i get it so it I want to add a new item in Work i can select that? Or add an item to Fun/Sport i can add it there type thing?

 

Thanks,

 

Dave