Good video series for using RN and Manual TDC: Browse on Youtube for the Stoianm tutorial videos. There are some very good ones including 4-Bearing method, hydrophone firing solutions etc. The Stoianm videos are old but they can be replayed 1:1 with the current TWoS.
I'm sure Peter (aka THEBERBSTER) can re-direct you to his sticky tutorials, see stickes above, by browsing them you should find what you want.
Currently I'm making personal notes about using Auto TDC without RN, and it's complex enough for me... It starts from how to setup your game in the Options (manual TDC activated or not), the changes in the OFEV (XO TDC tab), how you identify ships (optional TWoS mod needed), and finally the firing procedure itself.
All this is much harder than in other SH series, like SH3/SH4. If you don't play the game for awhile you can easily forget all this
