You are in fact greener than Druss assumed you to be. Here are some hints to help you in your hunt...

2 ch heli: One channel controls the throttle (rotor head speed to climb and descend) and another channel controls the rudder for turning left and right. Typical of the Picco Z and others.

3 ch heli: as before, you have rotor speed and rudder, but this time you might have control over a "thrust" vector or possibly another feature. There is really no good application for a 3 channel heli you actually need the 4th channel to have some sort of control. I've seen a heli like this advertised under the Air-Hogs brand but ca't recall the name.

4 ch heli: Here you have rotor speed (throttle) and rudder like before, but now you have the ability to tilt the heli left, right, forward, and back with cyclic control. So in fact you have 2 channels on cyclic; fore-aft cyclic (elevator) and left-right cyclic (aileron) and the previous 2 channels throttle and rudder. Typical of the twin rotor helis, and some single rotor helis.

5 ch heli: here you have the previous 4 channels (throttle, rudder, aileron and elevator) but add the realm of blade collective pitch. Before, you had up and down control with rotor speed (throttle) but everybody that has flown a fixed pitch helicopter can tell you a story or two about the yo-yo effect of fixed pitch helicopters. Here comes collective pitch (or just "pitch" ) where you have control of the angle of the rotor blades. This gives you additional control of the rotor head to prevent the yo-yo effect and even give you the ability of flying inverted when the time comes. Typical of the Trex, Raptor, and bigger sized helis. Main giveaway is the ability to fly inverted. Or "3D" a term loosely used these days.

Rafael