When the app starts, press to move over to ‘Library’ and select ‘Interactive Episodes’.
This is unlocked in Episode 2, ‘Baby Bear’s Baby Doll’, Chapter 1, ‘Jump for the Letter K Snack’.
When Cookie Monster tells you to jump up, jump until something falls from the tree. The kayak is the third (of four) item to fall from the tree.
The simplest way to unlock this achievement is using ‘Chapter Select’ to choose the chapter. When the chapter is over and the next one starts, just press , move over to ‘Stop’ and press again. The achievement will unlock when it is buffering. You can alternatively watch the entire episode, but that would be more time consuming.