I went with simple decoration on the invites due to the limited time I had to create them, the kids loved them and were so excited to recieve them from Mr E.
Here are the cutting and scoring measurements but I recommend watching the below video to see how the process worked.
Cut the cardstock to 9 1/2 x 6 3/4 inch.
Score at half inch on one side then flip and score ever 2 1/4 inch. Turn 90 degrees and score every 2 1/4.
Then selectively cut on the score lines to get the needed shape.