I've always found reading other people's programs was much more useful to me then to just tackle a reference manual from start to finish. Seeing functions and expressions written in context and used in a complete program just seems more useful to me rather then trying to tackle such in isolation. So I would load an example sketch and start reading it and if anything that seemed new or strange or unexplainable to me would then give me a context in which to search out a reference to help in 'decoding' what it does and how it does it. Works for me, maybe not for others.
Lefty