It's actually the reason I passed on this product the first time I tried it
I am glad I tried again, though!!
The pouch clip should be
open.
Put the wafer/flange on a flat surface and push the pouch on to the ring.
When you have the pouch on the wafer's ring, run your finger around the connection from the 'outside' part of the pouch (what would be facing out when on your body).
Once you have done that, push the clip together, hearing the 'click'.
Now, the important part, hold the wafer and the little 'tab' that is on the top of the pouch and try to pull apart. If they separate, go through the steps again. When the pouch and wafer are connected properly, they won't separate.