The box should be 2-4-8. Keep in mind that your box has no top. You can make your box out of one 4-8 piece of wood, two 2-4 pieces of wood, and two 2-8 pieces of wood.
NOTE: you can make your boxes different sizes, just use scale factors for the dirt, worms, ect.
Step 2: Starting the box
The two basic elements that make up compost are green garden debris (grass clippings or old annuals) and brown garden debris (dry leaves). Green ingredients are high in nitrogen and brown materials are high in carbon. All these items are required for a successful box. Use one part green to two part brown materials break down fastest.
Step 3: Adding the dirt
Add in about 2 shovelfuls of garden soil to help the the microbial activity in your pile.
Step 4: Adding worms(this step is optional)
Although this is not required, it helps to decompose. A 2-4-8 box should have about 500(you can use more for better results) worms.
Step 5: Checking moisture
Compost also needs the correct amount of moisture to breakdown. Compost with the right moisture level should feel like a damp, wrung-out sponge.Check your compost pile's moisture level once a week and adjust it if necessary by adding water to increase moisture or more browns to help dry the pile out.
Step 6: Keeping air
Turn the pile once a week to move material from the outside of the pile in. Turning also keeps the pile from compacting, which reduces airflow and slows down decomposition.
Step 7: Checking
You should have finished compost in about two months. You'll know your compost is finished when it no longer heats up and you can't identify any of the original materials. The compost should be dark brown, moist and earthy smelling. Dig finished compost into your garden's soil. You can use partially composted material as mulch.