I recommend maybe getting a medical terminology book to begin with. It will help you get used to the words and abbreviations used. If you haven't had A&P yet, it might not hurt to get A&P Made Incredibly Easy, or something along those lines. Same for microbiology and chemistry.
A med surg book is about medical-surgical nursing, which is probably one of the first nursing classes you will encounter. Before you get a med surg book, you might get a fundamentals book first, since it has basic stuff like skills (bed-making, dressing changes, etc.). I got one from the Incredibly Easy series, and it was helpful. There is also a med surg book in that series, if you are interested. I usually get some kind of book before I go into a course, just to get a heads up on what the course will be like.
For clinicals, I have How To Survive Clinical (or something like that), and it is published by Kaplan. It had alot of good tips in it.