Most of the ships operation is handled by periscope, but the map is a wonderful strategic tool. A time control can double the speed, or even make the game run 4 or 8 times faster if you haven't the patience of a true stalker. It's alright, I don't either.
I honestly can't sum the game up any better than the instruction manual below, so feel free to read it! Believe me, the game is too complex to figure everything out on your own. Keep a copy next to you until you're familiar with the instrumentation on the bridge. It really helps, as this gives you an accurate idea of your fore and aft torpedoes.
At some point, I almost always end up firing from my rear. Don't be afraid. It's a little harder to do, but it saves your forward torpedoes for later. It's nice to have that option, ne? To this end, I endeavor to spend my aft torpedoes on the tankers and cargo vessels. Of course, you could take out the escorts and destroy the tankers with your deck gun.