How do Hoop the back of a hat with a 9cm hoop?

The best way is to watch a training video like this on hooping a the back of a hat with a 9cm hoop. 

Go To Hooping the back of a hat with a 9cm hoop

I need some tips for sewing and Digitizing cap embroidery?
There are two rules for digitizing on six-panel caps. First, start the design at the bottom of the cap where it is most securely held by the frame and work your way up. Likewise, start from the center where the seam creates bulk and sturdiness and work out to each side, one side at a time. These two rules will result in more color changes and trims than if you digitized the design in one fell swoop, but the perfect registration and excellent runnability will make the extra time and effort worthwhile