You should have a thread to fit a small bolt in the frame for the chaintug to stop up against, put a bolt in there leaving the head on the outside for the snail cam to press against, undo the wheel nut or bolt, remove the chain tugs and place the snail cam on the axle in the middle hole of the cam then refit the wheel nut/bolt, turn snail cam to tension, tighten wheel nut/bolt. Job done!