In the past we've always had above-ground compost piles inside two wooden lattice structures with doors. One structure was filled with finished compost ready to be spread on the garden in spring, the other was an in-process pile.
Here, because we're in a city, and I'm afraid of rats slinking up from the "river" (in spite of the five or six cats that patrol the garden wall) I decided to put the compost underground.
El sr J digs me a hole:
The compost bucket is filled with fruit and vegetable peelings, eggshells and coffee grounds:
I dump the compost into the hole:
Sprinkle lime on top:
Dirt goes on top of the lime, and the hole is ready for two more dumps:
We've made five holes so far. I haven't determined how long it takes for the refuse to turn into loamy, wormy soil, but we have plenty of space for holes and time to let the stuff decompose.