The best thing to do is buy garlic bulbs at a local nursery or mail order during the late winter season. This will ensure you get a good variety that is free of disease. You can also use bulbs from the grocery store, but it can be hit or miss with regards to quality. Break apart the bulb and plant the individual cloves in a row, about 4" apart and about 1" deep. After a few weeks, you will see growth appear and the garlic will develop until about late summer when the tops die off and you harvest them. Basically each clove will grow into a bulb at the end of the season. It's pretty easy to grow.