I was lucky to be able to help out and participate. The Station Flight Director was Sally Davis and the two CapComs were Ellen Ochoa for shuttle and Lisa Nowak for station. Currently there are 13 flight directors but a big hiring is in the works for many new Station Flight Directors to be hired, as they will need about 25 to manage the station 24/7.
We were first given a briefing the evening before about the mission and how to use the headsets and communications system called DVCS (Digital Voice Communications System) which is a touch pad screen where you can choose from over a hundred different loops (all of which are recorded!). We were given our own loop to talk on (Prime Ops2) for the day. We chose a position to begin at (I chose Shuttle Flight Director) and then we would rotate through all of the volunteers.