More info wanted on compost bin

I want to make my compost bin from building blocks - I don't really know what you call them - the grey concrete blocks with two compartments!! I want to stack them up to make the three sides of the bin and then screw two channels of wood up the two front sides so that I can drop 2 x 4s into them. Is this making sense. The idea being that I usually take compost from the bottom of the bin and by removing one or two planks of wood at the base I can get to the compost. My question is is it possible to drill into the concrete blocks - I really should go and try for myself - and how can I stop all the planks from falling down when I remove the bottom ones. My DD had a great bin in Germany and it was so structured to make handling easy. Does anyone know what I'm talking about...lolol!! In that case, explain it to me...lol!!