ohgrant
IMO easiest way.
Start Sonar > Go to " insert"> choose "soft synth" select "CW TTS-1".
Select the midi track by clicking on the blank midi track, then go to "File" import midi select your midi.. Everything should be set in TTS automatically except BPM. You can adjust that in the project.
+1 here - this is an easy way to get the imported midi to play.
To the original poster: You indicated that you want to change some of the midi content. To do that with Sonar, you can read the manual, like we all did.
People here in the forum bend over backwards to assist folks with issues - but there is an expectancy in that person also putting effort into resolution of a given issue. You clearly don't seem interested in putting any effort into this, expecting people to do your work for you, and that is not likely to happen.
Bob Bone