Be sure you have two to three inches of skeg remaining. Prepare the skeg of the lower unit by filing or sanding any rough or jagged edges. Put the skeg on with rubber mallet or block of wood, but do not force. Using the pre-drilled holes on the Skeggard as guides, drill through skeg using 1/4" drill bit. Instructions are provided with Skeg, but this should give you an idea.