cordless screwdriver mate. and some glue they should probly have holes for the screws to go thru, or at least decent points at which to drill, use the glue to stick the top edge to the bodywork, and the screws to hold the weight of the skirt in place. make sure you get it spot on though or they'll look pants forever. you've got a bit of play with the glue as bodywork adhesive (tigerseal etc) takes about 4 hrs to set, so spend some time getting it right and use tape to hold it all in place before you drill holes.

if at all not sure, take a step back and make sure.