RE: Help getting started with a 4 channel transmitter?
Generally speaking, in the US, most 4 channel radios are set up with the primary turning control on the right stick.
So, if you're flying a 3 channel plane, your elevator and rudder are on the right stick and throttle is on the left stick. Left stick left/right does nothing.
On a 4 channel plane, your elevator and aileron are on the right stick and throttle and rudder are on the left stick.
Usually, while flying, you will only use the ailerons for turning unless you're doing some fancy stunts like flying 3D. The rudder is used primarily for taxing (especially with a steerable nose or tail wheel) and last second corrections while landing. (Actually I even use my ailerons during landing.)
If you look at a lot of the warbirds you'll see they don't even have a movable rudder, only ailerons for flying.