This third edition of the book has opted to omit a separate tutorial part for three reasons:
The complexity and size of sendmail as a topic have increased to the point where the nontutorial materials have exceeded 1200 pages.
As sendmail has evolved, it has tried to isolate the reader more and more from its internals.
The only tricky part of sendmail is still its rules and rule sets, and those are covered in two chapters dedicated to them.
In place of a separate tutorial, we decided to offer a guide to introductory materials in its place. As someone new to sendmail you might be better served by following this guide rather than attempting to read huge, unstructured chunks of this book.