It was by no means a silly question!.....There is a degree of improvisation...as all incidents are unique, and this one in particular had both aspects which aren't covered in our annual emergency training, and things on the standard checklist which couldn't be completed at the time with the information at hand. I didn't mean to sound flippant!
Basically there's an initial call on the airfield's crash circuit, which alerts the emergency services and the airport authority's control centre. This is usually done by the ATCO actually working the traffic...and consists of a/c type, location, problem etc. The Sup then has a few minutes to make a 'second call', with more details (callsign, company etc). Then the checklist goes on to give other agencies which need informing, and the information they each need.....Terminal Control, Area Control, AAIB etc.