Mounting it is typically a DIY endavor.
You can get a plain flat plate from AGK or you can make your own mounting plate.
The AGK plate is designed to use the mounts brackets from a Typical HuaSheng 142F style mount. You can also weld it to the frame or make your own mounting brackets/ clamps for it.
AGK also sells a jack shaft assembly to fit the HF79.
EZ Motorbike sells the Qmatic drilled to fit the HF79. Just tell them what you want it for before ordering or by default you will get one drilled for the HuaSheng 142F.
AGK sells all sorts of hop up parts for the HF79, too many to list here.
If you are skilled enough to understand what the techniques and risks are, you can also do some things yourself such as decking the head to increase compression and fitting a motorcycle or scooter carburetor.
Many folks here have successfully installed a lawnmower/ edger engine in a bicycle frame with no kit parts what so ever. Check out these forums for ideas and info:
http://motorbicycling.com/forumdisplay.php?f=6
http://motorbicycling.com/forumdisplay.php?f=36
Yes, there are plenty of threads to weed through...