An Owl's Birthday.
Print the template on letter size paper or A4. Let them dry completely for a couple of minute so it won't wrinkle when during the handling and cutting.
Next is to cut along the line. The envelopes might give you some hard time but the card itself is pretty straight forward.
To fold the card, align the outer edges first and then fold.
To fold the envelope, I folded the shorter parts first and folded + glued the bottom of the envelope.
Next is to write whatever you want inside the letter. Have fun!