If i remember, the front arches (bodykit) should have a thread on them - push it through the hole in the wing then use small washer and nuts to secure with a couple of screws on the end?
The back ones I cant remember - think maybe screws - if you find out let me know coz ive had new inner and outer rear arches done on mine so will need to get the kit back on too!!!
The skirts have a hanger riveted or screwed to the sill and the bodykit sill just screws underneath it? Again correct me if im wrong coz ive got to do the above too!