The theatre was built on a semicircular plan, and the hillside of the citadel supported its audience. Two vaulted passages still lead to the orchestra, a semicircular space occupied by the choir during the performances. In the case of the theatre in Ankara, it has a diameter of about 13 meters and is surrounded by a thick wall. Unfortunately, it is not known what material was used for the floor of the orchestra.
A proscenium, i.e. the platform where the actors performed, has also been preserved. Only the northern part of skene, the structure at the back of a theatre stage housing changing rooms and warehouses of props, has survived in Ankara. The choir used the passages called parodoi, of which the eastern one survived to our times in its entirety, and the western one - only in fragments.
The seats in the theatre and radially ascending stairs were made of stones, debris, and plaster. The auditorium was divided into four horizontal sections. It is estimated that the theatre had from 20 to 22 rows of seats and it could accommodate between three and five thousand spectators. Therefore, it is a relatively small example of such a building in Asia Minor. The seats from the audience were later used to build the walls of the citadel, although archaeologists managed to excavate two of them in their original location. They were made of andesite, and their height was about 40 cm.
https://turkisharchaeonews.net/object/ancient-theatre-ankara