Most radio sets include a transmitter (fancy name for remote) and a receiver (the little box in your model that your remote talks to). However, some don't. If you need a receiver, make sure the receiver is in the image or title. If you can't see a receiver in either of them it's likely a receiver is not included.
In general, you shouldn't need to worry about the maximum range of the radio as they typically go further than most people can see.
You might notice most brands don't list the range on the radio sets. But why? It's because the range varies so much from area to area. For example, out the front of our store we can easily get 100-300 meters with most radios. However, when we go to our local bmx track (that has a mobile tower .5km away) the range is only a quarter of what we'd get out the front of our store.
Typically just 2. That's because all cars & boats need throttle/acceleration and steering (1 channel for each). However, if you want to turn LED lights on and off separately to your throttle and steering input, let's say with a switch or a dial you'll need a 3rd channel.
Note: If you do want to add LED lights to your model you can do this without adding an extra channel if you're happy for the lights to turn on/off when you turn the model on/off. It's only if you want to control the lights with your remote (it's a pretty cool party trick) that you'll need a 3rd channel.