I'm not sure how much you know, so I'd suggest making sure you have an idea what different trades do and are responsible for in construction. After that, I would either search google for textbooks for that trade. You can also try and see what local trade schools use. It is important to note that code books (ICC, UPC) are for people with knowledge of a trade, but if you end up building an addition or something to your home you will probably want to read and learn those. It also might be a good idea to start with a book aimed at homeowners or amateurs, as it will get you started faster and will be significantly easier to read and digest. If you do build something, don't be afraid to hand certain things over to a professional, there are cases where it can be cheaper, easier, and safer to let someone with the tools and experience take on a job instead of doing it yourself. The next time you have work done, you can also just ask your contractor. Most of them are very friendly and will be happy to let you know.