We hope it is clear how to use MarsBaR, but please let us know if you have problems. In particular, we would be very glad to hear of any bugs or inconsistencies.
There is a mailing list for MarsBaR; list archives and instructions for posting are available via the MarsBaR users mailing list page. There is also a MarsBaR mailing list archive. Gmane also provides a nice interface to recent MarsBaR emails.