Christmas Linzer cookie cutter set

How do the cutters work? The fluted edges of the round cookie cutter cuts scalloped edges on the rolled out cookies. In the center of the cutter, there is a plunger that holds an interchangeable shape. To make a cut out, push the plunger down where it will make a cut in the center of the cookie.  After baking, the hole in the middle will allow the jam to peek through the Linzer Cookies.