@pidge32 To be sure the the details are clear:

The bag/wafer has a sticky part that constitutes a barrier. But many people also use a separate sticky barrier ring that goes between the bag and your skin.

I was originally taught to put the ring on the bag/wafer, and the put that on my skin. Since then I figured out it works better for me if I first put the barrier ring on my skin, and then put the bag/wafer over that.