1. In Platform click "Settings>Redeemables".
2. Click on the base redeemable tab.
3. Once this is done the base redeemable will appear below the base redeemable tab, click the name of the base redeemable.
4. Click the "Next" button in the lower right corner to get through the next 2 screens.
5. On the last screen you will see the "Remind Before" field, this is where you can set the number of days. Make sure to click the "Finish" button to save your work.