The following steps are a guideline and may be easier to follow if you watch the video first.
The same two circles can be used to create many different scalloped circles just by changing the location of the smaller circle and the number of columns used. Example shown below.
Remember, if you do change the location of the small circles to relocate the rotational centre. To have the small circles follow the perimeter of the larger circle the centres must be in the same location.