How do you change brake pads on a 1999 Chevy Malibu LS?

The best answer to this is to go to your local auto parts store, and buy a Haynes manual. It has step-by-step instructions with pictures that should make it fairly easy. To do this job properly, you will need to also remove the rotors and take them somewhere to be resurfaced and checked for thickness, if they are too thin you will need to replace them. Most machine shops and some auto parts stores will machine rotors.