Can you convert midi to audio

I have Sonar Pro but can't for the life of me work out how to convert or render Midi files to audio... I have a bass and drum midi tracks together with my audio tracks (vocals, guitar etc) and would like to turn them into a wave or mp3 file... When I try to export them as audio the vocals and guitar are exported but not the midis. Probably a simple answer somewhere I'm sure. Any help would be greatly appreciated...
Cheers

MIDI tracks need to be routed to a virtual (or external) instrument to make sound.  The output of a virtual instrument (VSTi) is an audio track in your project, that can be routed to a physical audio output in your audio interface so you can hear it through your monitors.
 
When you open up a General MIDI file in Sonar, it should insert the TTS-1 GM synth with the MIDI tracks already routed to the necessary GM sounds.  In order for this to happen, ensure that you have no MIDI outputs selected in Sonar options.
 
Routing path:  MIDI > VSTi > audio
 
If the MIDI file is not GM, you may have to set up the synths and sounds you want manually.  You can select any VSTi synth plugin and preset available for each MIDI track.
 
Once you have the synth tracks assigned, you should be able to press play and hear the sounds being played back.  When this is working, you are ready to create audio tracks from your MIDI.
 
Freeze Synth - Audio from a soft synth is bounced and placed on the synth’s track. Output from the synth is disabled, as is the effects bin on the synth track.  https://www.cakewalk.com/...mp;help=Mixing.23.html
 
Direct Synth Recording - Introduced in Sept 2015 - Thanks to direct synth recording, bouncing is no longer necessary to convert a virtual synth output into audio because you can now record the synth audio in real time.  https://www.cakewalk.com/Support/Knowledge-Base/2007013427/SONAR-2015-Ipswich-Update-Notes

davis
Thanks guys but I made the backing tracks (bass, drums, piano etc) in Band in a box and brought them over to Sonar Pro to put vocals to the track and edit the midi files and was hoping that I could render or export the whole song. The freeze button for the midi tracks is not there but is for the audio tracks (go figure). Is there any other way I can save the midi tracks as audio? Your help is much appreciated...

I cannot imagine why you don't see the freeze button? 
 
It is there on the oldest version which I have installed, Sonar 6.  Not exactly a new feature, but it's probably older than that.
 
Did you try using the F1 key to open the help manual?  Search for "freeze".  It also mentions that you can use the right-click context menu to access the freeze function.  That appears in the track strip for the track to the left of the clips.
 
Are you sure that you have the MIDI tracks routed to a soft synth?  The freeze synth function needs a synth to generate the audio with.

Yes I do hear the midi tracks (Drums, base etc) from front to back along with the audio tracks (guitar, vocals etc)...
The freeze button is present in the midi track but is shaded out. I can't click it...
However the freeze button is available in the audio tracks...
 
I have looked in the help index and this is the message there.
Note 2: A MIDI track can only be frozen if it is routed to a software instrument.
What does this mean?
 
Sorry for not understanding but with Band in a box you can simply just render your midi file tracks with your audio to a wave file when you're ready, it's very easy.
 
Thanks for your help...

davis
Thanks guys but I made the backing tracks (bass, drums, piano etc) in Band in a box and brought them over to Sonar Pro to put vocals to the track and edit the midi files and was hoping that I could render or export the whole song. The freeze button for the midi tracks is not there but is for the audio tracks (go figure). Is there any other way I can save the midi tracks as audio? Your help is much appreciated...

If you are hearing everything that you want to hear on playback, you can export audio without converting anything. File->select all then go to File->export audio, give it a name and select "what you hear." this will give you a stereo file of your mix.
 
Rocky