as above but i start with pushing the pistons back in first using old pads and discs to save damage to new items (remember to slacken brake resevoir lid off a little to allow fluid back.
also always fit new brake pads to new discs or you will create hot spots.
i also like to remove the caliper second as it can be messy and clogged with dirt which you dont want inside your hub and on the stub axle...