I made my own years ago and it was very successful. I used an old bin with a couple of small drainage holes in the bottom (I kept a tray underneath to catch the liquid. It makes an excellent fertiliser when added to water) then 4" of gravel in the bottom, then a foot of soil then loads of kitchen vegetable waste on top. Don't put onions or grass clippings in it. I went to the local tackle shop and got a tub of red worms and tipped them in. within 6 weeks it was making composted soil and supplying me with fishing bait. I had to empty the new soil out every year but it was brilliant for the greenhouse. Don't let it dry out and keep it in the shade.
Fetere sum, ego sum Ergo