You begin by clearing and quadruple checking the gun for ammo, take the slide off and remove the spring and barrel. Take your nutdriver and unscrew the small hex head screw holding the front sight. Be careful not to drop it it's tiny. Put the sight and screw in an envelope or zip lock so they wont get lost. Next, carefully remove the screw from the new sight put the screw into the hole in the slide (tweezers or a pair of fine nosed needle nosed pliers make this a lot simpler. Holding the screw with the nutdriver attach the front sight to the slide torquing it very snugly. Drive the factory plastic sight out from left to right and the new one from right to left. Eyeball the sight notch for center and you're ready to shoot it for zero. After zeroing, a drop of GREEN Locktite will keep things put until you want to move them again. I use a laser bore slighter to check for proper sight windage alignment before shooting. The sights on my G19 were dead on using this method. At the range you can tap the sight left or right to get the windage dead on if necessary.
It took me about fifteen minutes to actually do the work the tools needed are basic or inexpensive and you have the satisfaction of having done it yourself. Plus you have saved $35-50 by not going to a gunsmith.
Here's a VIDEO OF Dave Dawson showing how to do this job.
