Welcome aboard Bilge Rat
Dont feel bad man. I have been playing subsims since SH2 and Im pretty lost with this one myself. Just tried a mission with manual targeting and I gotta tell ya, I cant hit the broad side of a battleship.... literally

(just got SH4 recently)
Keep pluggin away, ask questions here and you'll eventually be the terror of the high sea's.

This has always been a great community full of very helpfull people so dont be afraid to ask.
Just dont ask me, when the IJN see's me comming they roll out the hot tea and sushi cause they know Im no threat.