Much of the useful functionality of Blue Sombrero is hidden in a grab bag of one-off reports. Lots of the reports are useless, but you will generally find one that gives you the information that you need.
To look up coaches, use the "Volunteer Details" report, which includes the names, teams, addresses, and phone numbers.
In this video, I show how to pull the report but I don't show the contents because I don't want everyone's cell phone on a youtube video.