I have had my s8 plus for 10 days and could find the manual in the settings menu.
Now its not there just a message saying it is not available in my language.
Mines still on my s8 @Sputnick007
Try a soft reboot by turning the phone Off and On.
Manuals can be found online perhaps via > http://www.samsung.com/uk/support/model/SM-G950FZVABTU
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.The advice I offer is my own and does not represent Samsung’s position. I'm here to help. " This is the way. "