Availability is a creator's bookable inventory over time, treated as independently open-or-sold time segments rather than one on/off switch, so a brand can book part of a stream and leave the rest open.
A creator's bookable inventory over time. Publsh treats a day as a sequence of time segments, each independently open or sold, rather than one on or off switch, so a brand can book part of a stream and leave the rest available.
Only one placement runs at a time, so the first booking to land on a segment wins it.