To fill calendar gaps for the artist you need to have casting data in the system, and the artist needs to have gaps between contracts / events. Go to the artist profile and select casting from the menu. On the right you will see 3 options, select automated gap filler. This will give you the gap filler. If you click on it you will see a list of gaps, with start and end dates shown within input fields and a search icon next to them. If you click on the search icon you will see all casting info for this search icon.