I'm very new to this game myself, I've never played the series at all. But after reading this forum and watching a few of the video tutorials some of the memebers have made I'm getting the hang of it.
Check out this link if you havent seen it already.
http://www.subsim.com/radioroom/showthread.php?t=108931
I highly recommend looking at all the ones on manual TDC targeting, they are very well done and extremly helpful.