Choose a pair of cufflinks while wearing a french cuff shirt with cuffs and cufflink holes.
Rotate the backing clasp on the cufflink to make a “T” shape, so the backing is parallel to the cufflink stem.
Fold the cuff of your shirt over so the two holes in your cuff are aligned.
Push the backing end of the cufflink through the outside button hole.
Pinch both ends of of your cuff together, and bring the outer cuff closer until you can push the cufflink through the holes in both layers of the cuff.
Rotate the backing clasp to keep the cuffs in position.