A proper service and maintenance manual should detail exactly what maintenance and repair operations should be carried out, when, and most importantly how
True, but welcome to the Civi world, I have copied a section out of a current manual for you..
INSTALLATION.
Before installing the engine on the aircraft, install any items which were
removed from the engine or aircraft after the engine was removed
Fine if you actually took it out and the muppet prior to you didn't just write engine removed, accessories removed, engine sent for overhaul. ...