If you were more specific, I could give a better answer.
Did you just want a rundown of everything in the I/O window?
"Master/Parent Send"
This controls whether the track will send any output to either its Parent track (if it's in a folder) or the Master track (if it's not).
I use this, for example, if I'm taking a direct guitar recording and splitting it to multiple amplifier plugins. A tuner, a bit of EQ, maybe a comp and an overdrive on the first track, with aux sends to my two amp/cabinet tracks. I don't want to be hearing the non-amplified guitar, so I uncheck this box.
The volume and pan faders below that should be obvious - they're just the track volume and pan.
Track Channels
As mentioned above, each track can have up to 64 separate channels of audio running through it. Each stream is completely independent, and plugins can listen from and output to any combination you want.
Sidechain compression is the most obvious example - say you want your vocals to "duck" the mix any time you sing, so there's nothing crowding your voice. Many compressors have a sidechain jack, so that you can use an external signal to compress the one that's running through it. By adding a third or fourth channel to the track, you create a space for the vocals to jump in without interfering with the main signal.
Sends/Receives
Sends and receives allow tracks to communicate with each other, and let you have more complicated routing than just a series of folders within folders. You can work with them both on the track they send from (the Sends column), and the track they send to (Receives). If I went to my Snare track in the picture above, it would have a Send to Jamstix NY with the same settings.
Most of the controls are the exact same as those on the track panel. Mute, Phase, Mono/Stereo, Volume, Pan, etc, they should be obvious.
Below those are boxes for audio and MIDI channels. On this track, they serve no purpose because I'm only using two channels. In the example above, though, this is how we'd send the Vocals to channels three/four instead. You could also send FROM channels three/four in a track to somewhere else. Maybe you want to take a feed from the vocals before they hit your reverb plugin - you'd set a plugin prior to that one to output on three/four, and then use the Send accordingly.
Above the pan fader is a menu box labelled (in the picture) "Post-Fader (Post-Pan)". This gives you some control over where in a track the send is taken from. The options are:
Post-Fader (Post-Pan): Very end of the track's processing, after volume, pan, and all your effects.
Pre-Fader (Post-FX): After your effects, but before the volume and pan. Useful if you want to adjust the original track without affecting anything on the track it's sending to.
Pre-FX: The very first thing in the track. If you want to duplicate a signal and send it somewhere else, this is an easy way to do it.
Audio/MIDI Outputs
I hope the name is self-explanatory. These allow you to use your various hardware outputs independently of the master track. I only have two outputs to work with, so it doesn't help me, but there are a billion things you can do if you have more. A custom headphone mix for someone while they record, for instance - make a track for the mix, create a bunch of Receives from the other tracks you want to be hearing, and adjust the send controls like they were your main mix. This is a perfect example of when to use a Pre-Fader (Post-FX) send - you don't to be destroying the headphone mix just because you're adjusting the main mix.