How do I add an intro and a exit to a track?
Use the Time-Sift tool (the icon with the horizintal line with arrowhead at each end) to shift your original tack along for the lenght of the intro (and probably plus a bit more - you can remove any gap later. Move cursor back to time zero and record your intro - it will create a new track
Move cursor to end of tracks (use the right double arrow icon - the one like a FF on tape/CD players). Then record your exit piece. A third track will be created.
You may wish to edit to tidy the gaps and/or do some cross-fades at the junction.