Brakes are a safety item so if you don't understand any of the instructions below don't under take replacing the brake pads.
Open the wheel lug nuts 180 degrees while the wheels are still on the ground (probably 19mm or 21 mm). Look in your owner's manual to see the proper jacking point for your vehicle. Apply the parking brake, put vehicle in park where applicable, jack up the vehicle on level ground on concrete or tarmacadam. Place a jack stand under the chassis for safety, roll down the window and leave the key in the ignition so you can turn the steering wheel from side to side. Remove the wheel on one side slide it under the vehicle ( for safety), do not work with your head or legs under the vehicle. Open the two guide pin bolts that secure the brake caliper to the caliper mounting bracket.. Open the brake bleed screw on the upper portion of the brake caliper and push the piston in the inboard portion of the brake caliper allowing brake fluid to be pushed out the brake bleed screw, close the bleed screw as the piston is pushed into the caliper just before the piston is nearly fully pushed back. The aim here is to prevent dirty fluid being pushed back to the master cylinder yet not allow air into the brake fluid system hydraulic system. Remove the brake pads on at a time and replace hardware and brake pads as supplied. Inspect the brake pads for even wear, inspect the caliper piston dust seal and caliper guide pin boots. Inspect the brake rotors for damage/serviceability.. Lubricate the guide pin with a little brake grease. Reattach the brake caliper, tighten the securing hardware, press the brake pedal several times to allow the brake caliper piston to seat the pads against the brake disc, top up the brake fluid as required, place the wheel back on the vehicle and secure the lug nuts, fully tighten once the wheels are on the ground, and repeat the procedure for the other side. Drive the vehicle applying the brakes several times ( do not over heat the brakes). After driving recheck the brake fluid level and recheck the wheel lug nut tightness.
Check you tube there are several good video clips to do with brake pad replacement.