Explain then please how you retract the pistons on the rear. This requires tools to do it.
The rear pistons should be rotated in, not just pushed.
And......... oh,yes, if you just topped the brakefluid reservoir, because it was low, (this is due to the pistons which get pushed out with the pads wearing), you might spil the brakefluid over the paintwork, which is quite agressive to paint.
Apart from this it is a real DIY, if you've never done it before. Also don't forget to clean the brakeshoes, use coppergrease on the slidingsurface, and don't try to push the locking pin in from the wrong side.
Before I forget, just release the bleedscrew, not to de bleed, but to make sure once a while you turn it so it doesn't corrode itself fixed for ever in the alloy brakeshoe.
Ehhmmmm, also brakes make your car stop, can be quite essential. So if you've never done it, don't take anybody with you on the first drive.
Sorry if I sound a bit sarcastic, but I've seen a crashed car after DIY brake maintenance done by somebody I know.