Welcome Briney

, I hope you have tons of fun playing the game.
While patching the game to 1.4 is a must, try not to jump to adding mods until you've found a good reason for it. Once you find a problem, you can search here and find answers (usually in the form of mods). Boring missions are not a good reason, as even with the toughest mods, like the unforgiving TMO you can search blindly for weeks without a single contact, or, worse, not manage to approach any ship without being spotted and blown out of the water like a tin can. I recommend finishing a carrer first in a good sub like the Sargo and then the Gato class, to get your bearings. While you do that, look around the Workshop to see what's been done so far
http://www.subsim.com/radioroom/forumdisplay.php?f=219.