field separator

I would like to have a - separator between the track number & artist. Like my single artist albums, they have; 01 - John Doe, but some how my compilation albums with different artists for each track do not have the dash separator. How & where do I get mp3 tag to put in a separator? so it shows up like; 01 - John Doe, 02- Jane Doe & so forth.

I take it that you want to modify the filename, right?
Use the function Tag - Filename (is a button in the toolbar)
You are asked to enter a mask for filenames which consist of variables of the tag names.
In your case I think a mask that similar to this would serve the purpose:
$num(%track%,2) - %artist% _ %title%

The dialogue for entering the mask shows a preview. Feel free to experiment.