The pawls are spring loaded aids against kickback. On the Shark Guard they can be locked in the up position when not wanted for delicate materials or when cutting lots of narrow strips. Otherwise they would be in the down position and ride on the stock being cut.
Using the tail hook
The Shark Guard has a horizontal hooked slot at the rear and a vertical slot forward. These slots are the mounting slots for this guard. The rear slots get hooked on the rear studs of the clamp. There is a safety hook that slips down over the rear stud to keep the guard from coming off when not intended. The newest version has a spring loaded latch design to keep the tail hooks locked in place.
You can see in this images that the guard can be left in the upward position by hooking only the rear slot and resting the guard on the front stud and brass bushings. This ability is beneficial when measuring between the fence and blade with a steel rule. The front slots just slip down over the front studs with care taken to use the smaller bushing diameters. With this done and your tail hook swung down into place, your blade guard is installed.