basic firing

[Zero Niner]

I suggest to use auto targeting for now, and familiarise yourself with the game. For a newbie to sub sims there's just too much to get one's head around imho.
Once you're comfortable and gotten used to the sim and how it works you can try manual targeting.
Myself, I prefer auto targeting. US boats had a number of people that together determined the firing solution - it wasn't up to the skipper alone.