In the plastic thing holding the jack etc. which fits inside the spacesaver in my boot there are a number of implements. One of them is a red metal thing. It looks like you should screw it into one of the wheel bolt holes to help you get the wheel on bit it's too big to fit through the hole in the wheel.
No it just about fits (although is a tight squeeze) just makes getting the wheel on a bit awkward ...
Some wheels need the brake disc retaining bolt removed. For examle my OZ ultraleggeras clearly say in the manual to remove the bolt. Of course I read it too late, tightened the wheel and damaged it as the spiky bolt went actually through the rim and made a small hole in it.
As it was a pain to put the wheels on with brake discs rotating on the hub, later I cut off the the spikes of the bolts and left just a flat head 12hex bolt to hold the disc with no spike.