Tom,
I've just had a look in the pdf manual for BIAB 2014. On page 393 there's an excellent tutorial that steps a user through using repeats and endings.

The tutorial even has it's own folder of songs in the \bb folder. You'll find these under...
- \bb\Tutorial - Repeats and Endings
It's well worth taking the time to work through these lessons and the associated material.
Regards,
Noel