To do a kickflip backlip you need to know how to backsideflip and back lip.

Step 1: First come at the object at a parallel angel with some speed.

 
Step 2: Then turn your shoulders and start the flip.

 
Step 3: Lift your legs and let the board spin freely.

 
Step 4: Catch the board and set it down (center yourself) on the object and slide.

 
Step 5: When you reach the end turn off and ride away.

Don't forget to celebrate because you just landed a very hard trick.