There’s no such manual that I’m aware of. The pins in these forums, and the regulars who post here should be able to answer your questions.
If you’re using the Observer glyph you’ll need to use pet:observer or pet:observer/felhunter instead of pet:felhunter
https://www.wowhead.com/spell=219450/glyph-of-the-observer
Example from my personal macros:
#showtooltip
/cast [mod:shift,pet:Felhunter/Observer,@mouseover,harm,nodead] [mod:shift,pet:Felhunter/Observer] Devour Magic; [mod:alt] Unending Resolve; [@mouseover,help,dead] [help,dead] Soulstone; [@mouseover,exists,nodead] [] Command Demon
Aforementioned pins:
https://us.forums.blizzard.com/en/wow/t/macros-essential-information/21139
https://us.forums.blizzard.com/en/wow/t/useful-macro-templates/42937
https://us.forums.blizzard.com/en/wow/t/macros-condensing-your-physical-keys/678238