It has been a while since I changed my brakes, so I don't remember what style caliper BMW used, and I'm not sure if the 750 uses the same style. But whatever you do, do not dissasemble the caliper. Take a good look around the caliper and do the least amount of steps to take the pads out. If there are pins going through the caliper and the pad, take the pins out and the pads should come out once you push the pistons in. If the caliper covers the pads, then there should be two bolts holding the caliper to the caliper bracket that need to come out. Remember that you need to push the caliper pistons in before putting the new pads on the car. You can use a c-clamp or a giant pair of channel locks. And most importantly, DONT FORGET TO PUMP THE BRAKES BEFORE DRIVING THE CAR.
It should be easy to tell if you have 750 brakes in your car once the pads are out. 740 calipers have one piston per caliper while 750 calipers have two.