Can someone tell me if this is a 4 channel receiver or a 3 channel reviever. If its a 4 Channel receiver, Where do you connect the battery??

Its a 4-channel.

You Y-cable connect the battery with one of the servos. That RX sort of expects to be used with an electronic speed control that has "BEC" function... supplying the RX with power from the motor battery.

If you read the lable... it says 4/B at one of the connection points... suggesting that if no 4th servo s used... that's where you hook the battery up. (and you could always read the instructions that came with it.... they explain this quite well... I have one of these RX's.)

Thanks. I have a firebird XL and I am new to connecting everything up.

What kind of motor do I need for a 2 Amp ESC?

That's a very small ESC. A Speed 280 or larger will easily fry it. Some of the GWS motors will work. Once you know which motor, battery & prop you need you can look up the current on their website. I'd say you're looking at under 30" wingspan (depends on the type of plane etc.).
Usually you would pick the ESC last - you figure out how much current the motor draws and pick one that will handle that much (leave a little extra capacity because the motor might be more powerful than you expect). Picking a plane, motor, battery, and propeller is a lot harder.

You could run the motor out of the Firebird using that ESC... nothing much bigger.

Would a 15 amp ESC be able to work with a speed 280 motor?and also whats the difference between a Speed 280 motor and a Speed 400 motor. Is it size or is it RPM......

Easily. A speed 280 shouldn't draw more than about 5 amps (it will if you put the wrong prop on it, but not for long!). A speed 400 is a larger and much more powerful motor. It will come much closer to 15 amps. It may be too much, I'm not sure.
Speed 280BBs are 280 sized but more powerful. Speed 300s are very close to the size of a 280 but much more powerful; they tend to spin a lot faster.
A speed 480 is a longer, more powerful 400. There are also speed 600s.