I'm almost certain that this has been mentioned before in this forum, but it bears repeating for the newbies among us, those who have forgotten about it,
et al. Microsoft provides a huge number of
free ebooks about using their software products.
At the present, there are approximately 500 such books available. Lots of the ebooks come in all three of our favorite flavors--mobi, ePub, and PDF. A smaller number, it appears, come in only PDF, and some come only in proprietary Microsoft formats like docx.
I suggest that you follow one of the following links to start your exploration:
For Windows Users.
For Mac Users.