1. This birthday card has sound, so make sure your volume is on. 2. Maximize the screen using the button at top right of bday card. 3. Press the green flag to play. 4. Enjoy!
I used the book Coding Projects in Scratch - Now with Scratch 3.0 Revised and Updated. Birthday card project is on page 82. I added a few extra sound "bites" at the end to personalize the birthday card.