How do you disassemble a 9mm?

Answer 1

It depends on the specific model. Takedown procedures vary between firearms, but the one thing which remains consistent throughout it to remove the magazine, pull back the slide, and visually inspect the chamber to ensure that it's clear. For a SA/DA/DAO/DAK pistol, most models, you'd lock back the slide, engage the slide release (on Sigs and Berettas, you simply turn it, whereas you have to remove it with the Jericho/Baby Eagle - again, it varies between pistols), then pull the slide back to unlock it, and remove it from the frame by pulling forward. Striker fired pistols such as the Glock may require you to - after clearing the weapon - pull the trigger to decock it, then pull down on the slide release, after which, you'd pull forward on the slide to separate it from the frame.

If you're uncertain about the takedown procedures for your specific pistol, your best advice is to go to a gun shop or gunsmith, and have them show you how.