This procedure is necessary if you want the checkout to display a fixed set of products, regardless of what the user has previously added to the cart (session).
Procedure
1. Access the Checkout editing screen.
2. Click on the Cart step (or tab).
3. Locate the Product Source section.
4. In the dropdown menu, select the Select manually option.
5. The section titled Products in Cart will appear.
6. Inside the text field (textarea) under the title Products in Cart, enter the list of products that should be included in the checkout cart.
(Note: Product entry is managed by the cartBuilder component and requires a specific format, usually product ID and quantity).
7. Complete the checkout configuration and click the save button (usually Save changes or Save).
