Diapers boxes can be hard to get into. Especially if you only have one hand to spare because you've already got your child up on the changing table.
Here's what I do. I turn them over and open them upside down. Whereas there is packing tape on

the top which likely will require scissors, there's only glue securing the bottom flaps. Glue that easily gives way with a little bit of pulling. This is true of every brand I've seen.
I hold the box steady with my foot while using one hand to to pull up one flap and then the other.

Easy peasy.
You're welcome.
♦