Next take the two curtain pieces and fold them in a Z with the curtains on top and in opposite directions. Center them closed on the large back rectangle. Glue only the back section to the large back rectangle. Be sure they are centered together horizontally and vertically. And glue the medium blue rectangle with the writing and baby shoes over the seam (second pic above).
Now slip the “curtains” through the loops on the front of the card and try to make the “curtains” slide open. If they slide then you are done.
As I said, I tried this card several times before I got it right. You might want to start by gently taking the parts together and then solidly gluing them when you are sure you know how they go together.
And your Theater Style New Baby Card is done! Remember, it fits in an A7 envelope for mailing.