In case you weren’t aware, batting has a back and front (thanks to Pam Holland for teaching this to us at Empty Spools a couple of years ago).
I came up with a way to remember which way it goes: Dimples are on the face, and knobbly bits are on the bottom (interpret that whichever way you want!).
So, the dimple side faces the top and the knobbly side faces the bottom. Easy peasy!
(The reason why you put batting in the ‘right’ way is that it’s designed for the needle to punch down through the dimples, in line with how the needles punched the batting when it was made. If you have the batting in the ‘wrong’ way (knobbly bits facing up), then the needle struggles harder to push through the batting and may bring back up bits of batting with it.)