Armorer manuals are provided to students during armorer classes.
They aren't "technical manuals", but are written to assist the armorer who has already received current training and learned to apply the manual contents in a 'hands on' classroom environment while observing, and being observed by, a qualified instructor.
Yes, the manuals can be informative and educational when it comes to learning about the way the firearms operate and function, but they aren't something intended to serve as a 'correspondence course' in training someone to become a qualified armorer.
The manuals make a good reference for someone who has received training.
FWIW, I've found the notes I've taken during armorer classes to be very important when it comes to explaining material in the manuals, often adding further details and explanations provided by instructors, as well as supplementing the manual with things that aren't included in the manual.
Also, manuals are often updated as new manufacturing methods are introduced to the extent that it may affect armorers making simple field repairs (a field repair being a repair done outside the factory).
Design revisions and new model variations can also require occasional changes in armorer manuals. Sometimes a model variation may not be included in a manual, or not covered in any great detail, instead being discussed by an instructor and addressed during a class, with the student making whatever notes he/she feels is necessary to allow him/her to maintain & repair that model variation.
It's always interesting to hear how different instructors teaching different classes provide different levels of insight and experience over time, as well. Think of how one instructor who spent many years in production might have something different to add to teaching the class compared to another instructor who may be a retired cop who was hired and trained to teach armorer classes.
The manuals are generally written and created by the S&W Training Academy, BTW.