What is the best way to attatch this mounding, using new clips?

Do I insert the clips into the body first, then clip on the moulding? Or, do I somehow guess-timate where each fastener attatches to the moulding and try to press the entire thing into the body, hoping I have accurately lined up those fasteners to press into each hole?

This is the 4' section of sill trim just below the doors that attatches to the rocker panel using 14 plastic fasteners.

I have the new fasteners from RPR. They employ a bulbous, splined nose that inserts into each body hole. The flat, rectangluar "clip" part sits against the rocker and this is the part the long trim mounding snaps over.

Down the center of the thing is a cylinder. It sticks out from the car about 1/2". (Caution: it somes out, so handle carefully so you don't drop and loose any!)

This cylinder looks to be a sort of "plunger". It sticks out way too far to allow the moulding to contact and clip over the fastener.

I surmise this plunger is used to be pressed in toward the body so as to spread the splined nose and friction fit it against the inside of the rocker.

Do I do this first, then try to clip the moulding on? How do I push those plungers in? I don't think I want to tap them with a hammer, for fear of snapping the clips.

How is the moulding then attatched?