Bill Wallace, head of gunsmithing and technical support at XS Sight Systems, will show you how to install XS Sights on a Glock handgun. Installing a sight on a glock is a simple process if you're familiar with firearms already. To install XS Sights on a Glock pistol, the first thing you'll want to do is unload or verify the unloaded condition of the Glock firearm. Remove the magazine and lock the slide to the rear. Both visually and physically inspect that there are no rounds present.