How to mount a ham?

I bought a Serrano ham on sale. It's the whole pig's leg, and it comes with a kind of a stand. However, the stand was delivered in pieces like IKEA furniture, but unlike IKEA, it has no manual explaining what goes where.

I'm especially puzzled about the large ring and the small trapez-without-base shaped pieces. Once must go up to hold the ankle, the other one down to hold the haunch. But which goes where, and how do I fasten the ham to the metal? Do I have to screw the metal screws through the bone?

The picture shows all parts delivered, only the inbus key is not in the frame. I put the trapezoid part onto the lower hole and started fastening it with a pointy screw; it's quite a long screw (7-8cm).