Make sure all parts are included. You should have:
An optics mount
Make sure the pistol is unloaded and safe.
Install your optic onto the mount using the 6-32 screws that came with your optic. Do not exceed 7 in-lbs! Inspect the bottom of the mount to make sure the screws don’t protrude below the bottom of the mount as shown (Docter pattern mount shown):
Install the optics mount onto the pistol, using the original screws. Do not exceed 12 in-lbs!
Perform a function check and make sure the pistol is safe to fire.