The best way to learn a second language is always to become familiar with it. If the sentences, words, and order of letters do not make sense to you and you feel like you're seeing hieroglyphics then something's wrong. I'd like to believe that you only found the book helpful due to your previous acquaintance with the language through the audio lessons and since English and Spanish share the same alphabet (minus some letters like the ñ) the first hurdle is overcome.
I believe the next step you need to take is start reading Spanish literature or articles about things that interest both of you. With your newfound book, a dictionary and a second mind beside you, you'll learn in no time. Best of lucks!