Place the bed skirt over the box spring. Smooth the bed skirt so that it lays evenly across the box spring, and so that the edges of the bed skirt are the same distance from the floor on both sides.
Insert the first bed skirt pin at one of the corners near the head of the box spring. Push the bed skirt pin into the box spring until you reach the bend in the pin. Push the top backside of the pin until the bed skirt pin sits flush on top of the bed skirt. Repeat this step with a bed skirt pin at each corner of the box spring.
Slide the mattress on to the box spring. Align the edges of the mattress with the edges of the box spring. The bed skirt will stay in place throughout this procedure.