The airport will be located south of Berlin, 18km distance to the city center (Brandenburg Gate/ TV Tower)
The airport will be connected by S-Bahn (green)(overground rail metro), by an express airport rail shuttle (red) with 20 min ride to the Central Station, by regional rail and HSR in North/South East/West directions. The rail station will operate directly under the main airport terminal (center of the pink area). Of course it is also connected by Autobahn(orange).
It will use 2 runways, with a starting capacity of ~27 mil. passengers. Future (potential) satellite terminals (horizontal blue buildings) can expand the capacity to ~50 mil. passengers. An additional 3. runway (not yet envisioned or planned) could be built in the South (right part of the image)....
The new airport will become the inner European Hub of Air Berlin.