midi to audio

Yes you can. You want to use your sounds from the  tyros 5 I suppose ?

Assuming the Tyros 5 has only one stereo output pair, you will have to record the audio output of each track one at a time (or two panned hard left and right if you don't need to capture stereo imaging and FX). So it can be done, but not quickly.
 
Basically, you'll need route the audio output of the Tyros into your audio interface, slave SONAR's clock to the Tyros MIDI Clock, set a matching project tempo, solo a track in Tyros, and record it in real time to a track in SONAR. Then repeat for each of the other 15 channels/tracks. If it's a typical 4-minute song, this will take a while. 
 
If you're willing to forego using the Tyros as a sound module, you can export/import or record the MIDI tracks into individual tracks of SONAR in one go, and then use soft synths to generate the audio. but you'll probably spend as much or more time setting up all the soft synths as you would recording individual tracks from the Tyros, so it's your call, depending on whether you feel the song is totally finished in terms of the composition and timbres, and all you want to do in SONAR is mix and master.
 
CORRECTION: I should have said slave the Tyros to SONAR's MIDI clock. Since SONAR is recording audio, it will have to be locked to the interface's audio clock.

thank you. I will print it out. btw. Sibelius 1801 is out. Showing more Promise connected to a tyros 5 for some reason without a soundset file

onboard soundcard. AG. yamaha mixer. 6 channel

 
 
 
It's got to be the most complicated task I can think of to extract  multi tracks from a stereo output audio system.
This involves:
A proper audio interface so the tracks will be in sync
your clock needs to be accurate. 
Figuring out how to use midi sync.
having to record in real time
Have to make 8 or more real time passes to capture.
Having to mute the different instruments on each pass. 
You asked for quickly, the audio transfer will not be speedy at all. 
 
Your going to run into timing issues using an on board sound card as well so you will need an audio interface.
 
I know people get used to the sounds from those keyboards,, but really, honestly there are equal and much better sounds available as VST instruments. 
 
Your problem is easily solved by simply exporting a midi file from the Tyros. 
Then Open that file in Sonar and use the many VST instruments to create your song..
This could be done without a proper audio interface. But if your planing on recording guitar or vocals later you'll still need an ASIO audio interface.