Yep, screw thru the plate like your first pic... Spring... Pickup Cover (clearance hole), Pickup (threaded hole)... hopefully wires are long enough to assemble then turn over and fit guard...
Put a bit of cardboard across the pickup cavity to hold the pickup up, pickup cover on, then spring, cocktail stick... lower the pick guard over the 4 cocktail sticks, then swap each stick for a screw into the pickup untill it catches a bit, then hook the card rests out...