i have bought the game but i never played it before the other install had a download manual but i cant find it, i have opened the map where the game is installed too but cant find nowhere,
ediy: nm i searched it in the browser and opened from there.

go to the browser and click on libary to dnd stronghold left click on the game name in you libary left click on manual and then it ask if you want to dl it or open it choose open with and then you get the manual

alternatively in Galaxy
select stronghold ,
click the more button
on the dropdown menu click extra downloads
the manual should show up to download
it should dl to your galaxy install location
(for me its C:\Program Files (x86)\GalaxyClient\Games\!Downloads )

thanks thats it!