The redemption code is located on the slip of paper inside the box that says "Set Up" in red font. The code is listed under "Step 2" in a white box.
Once you locate your code, please use the browser on your device to navigate to https://my.playosmo.com/redeem and follow the instructions on that page.
The Starter Kits can also include a QR Code on the Quick Start Guide instead of a redemption code. Scanning the QR code will unlock your games.