Hay infusion is a method of making a suitable home for your microorganisms to grow, this is achieved by boiling hay with water. This results to a broth, rich with carbohydrates and other "food" for...
You really can't, however, the best way to start would be to find a way to keep oxygen in the atmosphere, so that you could grow plants and then introduce primary, secondary and tertiary consumers.
you cant build one but an eg would bcat fish eat big fish big fish eat little fish little fish eat plankton (if you have any in a fish tank)you cant build one but an eg would bcat fish eat big fish...