[Delboy]

To change the brake pads the caliper needs to be opened using software (vcds) but you would need the cable and a suitable windows laptop to do it.

But being as you are having trouble releasing the hand brake it's likely not to open anyway.

There should be a ikea style crank Allen key type tool in the tool set that can be used to wind the caliper open in the event of electrical failure.

I would have a go at doing that first when you check the electrical connector.

Do not at any time try and squeeze the piston back in like you would on a traditional caliper.

Good luck and welcome from me too.