There is a great video on how to do this below but a couple of tips.
Note in the video john moves the handle of the screwdriver upwards to release the brake shoes . This only applies on the LHS .I just did the RHS so far and moving it down releases the shoes.
There is no auto adjuster on the handbrake so when you re adjust the shoes out dont take them right up to the drum as you would in a drum brake car as you will have no travel on the handbrake ..not dragging is the go and check the hand brake after .
If you are doing one side at a time you will have to lift the other wheel or you cannot rotate the drum .
Photo below of the pads . Note the abrasive patch ...would be good for used glazed discs but we will see how we go on the new ones. I had to break the three pronged thing off as it was not going into the hole in the piston which is a lot smaller than the front.

and for the video this is the one where he does the rears note its the LHS

 

That 'gotcha' got me too. I originally sourced new rears from the local motor factor:- identical shape but same story with the clip into the piston. Thankfully in the middle of other work so no extra down time getting the correct ones...

 

I dont think its an issue . Just to stop the pad moving while you fit it . I suspect later cars had a bigger hole in the piston as the piston diameter is the same as the front. These pads may fit multiple vehicles some with bigger holes in the piston so what do the makers do?.
I dont think its to help pull the pad off the disc, as my brake expert said when asked "what pulls the pads off the disc " ......"what is there to push them onto the discs ?"

 

no such issues when installing the ebc pads on the calipers, front or rear, on my ‘02 XKR.

Regarding what pulls the pads off of the rotor when the brake is released, it’s the rotor run-out, the same as any other car with disc brakes, not some pad anti rattle device.

Z