Playing 17 Track Midi Through a Soft Sythn

I just downloaded  to Sonar X3 Studio, a 17 track Midi file, You Raise Me Up. What must I do to pipe the audio (all of the tracks) through a Soft Synth?  

dubdisciple
Is this a midi file you made or a general midi file from the internet? If the latter . I would first try with TTS-1.

Thanks much for the answer.  I downloaded the midi files from the following link  
http://www.free-midi.org/song/josh_groban-you_raise_me_up.html
 
I managed to find a tutorial  and played around a bit with TTS-1   ... neat capability there.  Just tossing it out ... if anyone has a nice mellow midi version of You Raise Me Up  I would really love to use it.   My wife wants me to sing and record it; but, as someone commented on one of my recordings, transposing audio  can make the backing track seem weird so I am going to try working more with midi files for backing tracks.  There is much to learn but it is still fun!