Hate to be the bearer or bad news, but if that is the only port on the transmitter, that means the transmitter isn't buddy box compatible. The port in the second picture is the charge port for rechargeable batteries. Some radio's that don't come with rechargeable still have them built in, but don't use it if you fly with dry cell batteries.

In order to buddy box you have to have a transmitter with a trainer chord attach port. Most cheap radio's like Nitro Planes sells wont' have one. If you want to buddy box you'll need to upgrade to a Futaba, JR, Airtronics or Hitec radio (most popular in the US/Canada) with buddy box capability, and get second transmitter (usually of the same brand) that is used as the actual buddy box. Go to your local hobby shop and they'll be able to help you out.

Hogflyer