Mike
If you want to delve into the 'technicalities' of Radio Control, I can recommend :
"Theory and Practice of Model Radio Control" by Paul Newell – it's out-of-print now but I got a used copy off Amazon.
However, with modern 2.4 GHz kit, you can take the 'black box' approach….ie the Transmitter (you) sends a signal to the Receiver (boat) and this, in turn will move a Servo connected to the rudder(s). To control the throttle, you use another servo if the boat is powered by an IC engine, or, an ESC (Electronic Speed Controller) if powered by electric motor(s)…
Thus, it really becomes a matter of how to install and test it all in the boat. Here, I would recommend joining a model boat club as they will advise you on how best to do it on Your boat. There are many detail items to consider that probably won't be covered in any book.
Hope this helps,
Dave