The trouble with a lot of technical documentation, particularly man-pages and in-tool command-line help, is that it usually seems written as a reference/reminder for people who know more-or-less what they are doing already. You can often work things out from a more standing start, but that sort of documentation isn't optimised for this so you have to work for your illucidation.
For popular technologies there are often books, tutorials and other introductory articles. Git certainly has enough information to start out without reading every manpage.