The steps for booking breakfast takeout for the next day using the app are as follows:

1. Open the Meituan app interface and click on takeout.

2. Then find a food you want to eat.

3. Then select a delicacy, then enter the store, then select a breakfast to be reserved, and click to purchase.

4. Click to enter the merchant page, click the details option, and see the merchant's contact information. You can make a call to communicate about the delivery time and location, as well as the settlement method.