Step One: Put the extension between the tool's jaws and sqeeze the handgrip. This pushes the pin out far enough to pop the ball plunger out of the pin's groove, but not far enough to let the pin fall to the ground.

Step Two: Use the smaller jaws to grip the protruding pin. Clamp the jaws shut and remove the pin from the extension. To avoid losing the pin, keep the jaws clamped until you're ready to reinsert the pin.

Step Three: After reinserting the pin into the hole, unclamp the jaws and tap the pin into place with the backside of the tool.