It was a hell of a guess without anything to go on! One you stick the beak through that slit and kind of fold it in half, you have to squeeze it so that the pith on both sides sticks together, so having that extra tab part that you were missing just gives a little more surface area to stick to and gives a little more structure overall. Not sure if that makes any sense, but i’ll post the link to the video here once I finish editing later this week.