Section 1.4 Where Next?
If you are impatient (sometimes a good quality!), then Chapter 2 should be next, where we walk through the steps to construct and convert a couple short examples and then expand them slightly with several additions.
If you would like a general, high-level overview of features skip ahead to Chapter 3.
In-depth, comprehensive use of features is in Chapter 4.
If you have an existing project authored in LaTeX you may be interested in the conversion process described in Appendix H.