The pocket hole is an angled pilot hole ... of your jig should have a chart (like Kreg's chart) to help you select the proper length of the pocket screw, based on the thickness of the wood.

Kreg pocket-hole joinery is the fast, strong, easy way to join wood-drill, drive, and done Customizable Setup: This pocket-hole jig has a 3-hole drill guide for pocket holes, perfect for use with ...