When arriving by U2 or Schnellbahn train: take the exit towards Kaisermühlenstraße, cross the street, step through the building (on Erich Fried Weg) and go right, along the backside of the building until you get to the meeting room (it has a glass front so it should be hard to miss).
Important: Google maps doesn't recognise the address, so what is being displayed here is nonsense. Use this map instead.