Funny you should ask! I just watched this tutorial this morning and had to go find it again. It looks like there is a certain point where the pins go in. It's hard to tell as there is another 45 degree join in the video.Wish it wasn't there.
https://www.youtube.com/watch?v=j8N6nv90H2c
It looks like the join might not be a full 45 degree join. I can't quite tell. The last time I used flange binding, I had to use a straight join.
A second one here.
https://www.youtube.com/watch?v=7jqrs7wLyso