Select a sound according to the given register and sound quality. Always play the same sound (without changing its pitch) according to the indicated phrase duration. Make an even swelling and fading over the entire phrase length. The maximum dynamic which is reached in the middle has to be determined by the player. After you have played one "drone" make a pause according to the indicated pause duration. Play the same drone again, followed by a pause. Alternate this as long as the whole structure lasts.