John, I can give you the basics of what you want, but you must try to explain a little clearer what you are expecting to happen. I'll give you some choices to make things a bit easier.
First, some terms.
We'll call your Tyros 5 your "keyboard", it'll make things easier.
"Soft synth" = a software synth loaded in Sonar.
Audio = what you hear.
MIDI = what you're playing
1) you want to play your keyboard and record the audio in Sonar to mix later.
2) you want to play your keyboard and record the midi in Sonar so you can edit it, then play back from Sonar with soft synths as audio.
3) you want to play your keyboard and record the midi in Sonar so you can edit it, then play back the midi as audio from your keyboard.
4) some combination of the above I missed...
All the above are easy to do, but they are slightly different processes. Which do you want to do?
The simplest...
1) connect standard audio cables (1/4" jack) from the audio outputs on the keyboard to the line inputs on the 6i6
Right click the blank area on the Sonar screen and select insert new audio track
Assign it's input to the line input you used on the 6i6
Assign the output to the 6i6 outputs where your speakers or headphones are connected. Usually outputs 1+2
Press the input echo button on the audio track to hear what is coming into it.
Arm the track to record (press the little red record button ON THE TRACK.
Press 'R' (or the record button on the transport bar) to start recording
Play your keyboard
Adjust the keyboard output volume AND the input level on the 6i6 to get a reasonable level in the track. Between -12 and -6 is a good start.
Press stop when you're done. Press play (or space bar) to playback and hear what you recorded
There, that's a very simple, quick rundown of how to record audio.
If you need steps for options 2 or 3 then you're getting into the realms of midi. Just ask.
Karyn.