1. Unscrew the 2 screws 2. Remove the 2 screws and the first mobile part of each end (they have a round - oval shape) 3. Place the adapter on rails, but make sure you start from the back of the saddle and push it in the front of the seat 4. Place back the 2 mobile parts, one by one, and screw back the screws making sure the adapter is the right position 5. Make sure the saddle angle position is correct - if not loosen the lateral screws and move the middle part of the adapter.