Different compost heaps may be ready at different times for year-round usage. The first layer should be made up of course material such as leaves, weeds, stalks or hay to allow ventilation at he bottom. About 2 cups is enough for a bind that's 4 X 5 feet. These act as activators for the compost heap. Keep the heap moist but avoid too much water.
Ventilation is important so turn the pile with a pitchfork once a week.
You can also poke a pipe or stick into it and remove it leaving a tunnel for the air to get through. The time required for the processing depends on the amount of heat generated within the pile, the level of moisture, and the materials used. The heat will also be responsible for killing off weed seeds and some plant diseases. It's ready when it has decayed to the consistency of peat moss. This could take anywhere from a couple of months to a year.