Barry! Good to see a post from you. How are things?
I have not changed pads/rotors on an M5, but it shouldn't be hard. Those that have done it will probably respond shortly.
To change pads, you simply spread the old pads a little and lift them out. Then drop in the new pads. There should be some sort of retaining bolt/clip/etc. holding them in place. Should be easy to see.
On rotors you need to remove the caliper. This should be a bolt-on job. Do not remove the brake line - but, support the caliper so NO pressure pulls on the line. This way you will not have to bleed the brakes. I usually hang a caliper on something with a coat hanger.
Hopefully someone will give you specifics for M5s shortly.
Take care!
