—adj. giving or pertaining to basic instructions and directions to the layperson on the methods for doing or making something, esp. as a hobby or for practical use: a how-to book on photography.
—n. 1. a set of step-by-step instructions for accomplishing a certain task or reaching a certain objective: a how-to for fixing a leaky faucet. 2. the basic principles or approach for doing something: the how-to of investing in the stock market.