Like others, I've struggled some to make sense of BM3. I've spent the last couple of weeks thrashing around in the program and taking notes as I go along. I'm sharing those notes here in case they might be helpful to others.
If you notice any big errors, please let me know and I'll do my best to fix them.
Please note that this is not a comprehensive guide to BM3. The BM3 manual is very comprehensive and is worth reading. These notes are simply observations on parts of the program that for me are key to understanding how the program works.
I hope some find this useful.