So, Okay...
from viewing this video
https://www.youtube.com/watch?v=TqZO4qWVg88 and looking at my own setup...
I'm going to spitball & say that if one is running Sonar Profession, Artist -- we are stuck w/ the 2 standard themes.
Since I have no edit button there's no way to open and install themes. There's a /SONAR Themes/ folder in my /Cakewalk Content/ folder. but alas copying Craig's "Mercury with White Control Bar.sth" does nothing.
Sad trombone.
Ah well. That's too bad. I was hoping to get a new silver white, or pale white theme to use.
I'll put in a feature request. I'll check in here after the updates. Thanks for the good faith replies y'all.