If I have done volunteer work in the past, how do I add this information to the website?

Go the the Add a Listing page, and choose "Past Work."  We are hoping that information about work in the recent past will still be relevant, so we have arbitrarily chosen 5 years as a limit, but if you feel the information in the more distant past would still be helpful, please feel free to use your judgment.  

The goal is to help pediatric surgeons who are returning to the same region, so that they might build upon prior experience.