Until 2019 shipping small parts would always be cheapest by post.
Starting 2020 this is no longer the case, especially outside the EU.
The wheel adapter has the smallest production runs of all Mister Vee products.
As a result Your wheel adapter may be put together differently than described here.
It comes to you fully assembled.
To mount it to the wheel, disassemble it so you end up with the central disk with protruding threaded bolt.
Mount it to the wheel with the included screws if those turn out to be of sufficient length.
Otherwise mount with the supplied threaded rod and spacers.