According to Airac 2305; for P2ATC -> Taxi Mnt -> search for airport ICAO code -> Save/Load tab -> Load Airport Taxiways (choose the xxxx_Taxiways.gxl file from the download [replace xxxx with the ICAO code of the airport]) & Load Airport Gates (choose the xxxx_Gates.gxl file from the download)

Unfortunately runway assignment for takeoff/landing only and/or preferential runways cannot be exported, so you have to set it yourself, so e.g. P2ATC doesn't give you an arrival to a runway that is only used for departures in real life. You can google this for most airports really quickly or just look at the Navigraph charts (general airport infos).

For EGLL I have set 27R and 27L as Pref Light Wind runways.