Now the fun part begins. I thought a while about how to mount the parts to the concrete block, many people used these anchor bolts or simly reversed bolts which sticked with the head in the concrete. I kinda didn't like that solution of bolts sticking out of the block, so i tried on a testing block if a spacer nut welded to a short piece of rebar would work properly in concrete without breaking away:

The results actually surprised me a little, even after only a few days of curing time  i couldn't force the spacer out of there (with a bolt, a washer and a piece of pipe between the washer and the concrete, so it could properly direct the force to pull on the spacer). I only used a 1/4" Ratchet to be fair, but nevertheless it worked without breaking free:

After this successfull test i welded together 36 M6 and 8 M10 Spacers with pieces of rebar.. Plan in some extra time for that, because that will take longer than you'll think ;-)
But of course if you don't have a welding machine, you can use bolts secured in place with nuts. 

After some hours of welding you should finally be able to screw the rest together, don't overtighten the bolts, the spacers should sit flush on the melamine surface, not too loose so the councrete will sneak it's way into the spacer, but not too tight so the spacer eats into the wood and sticks out of the concrete later. Now you should have something that looks like that:

In this picture the M10 Spacers are still missing but therefor the 40mm pvc pipe is already inserted, which will act as placeholder for our main shaft.