Question 111 - Certified B2B Commerce Developer discussion

To introduce new screen behavior in a checkout flow step, a developer should clone the appropriate subflow and replace the Lightning web components in it. A subflow is a reusable flow that can be invoked from another flow as an element. A checkout flow is a flow that defines the steps and components for the checkout process in the storefront. A checkout flow consists of several subflows, each of which corresponds to a checkout step, such as Cart, Shipping Address, Payment, or Order Summary. To introduce new screen behavior in a checkout flow step, a developer should clone the subflow that matches the checkout step they want to modify and replace the Lightning web components in the cloned subflow with their custom components. The developer can then update the checkoutSteps.xml file to point to the cloned subflow instead of the original subflow. Modifying the property mappings in checkoutSteps.xml is not a valid way to introduce new screen behavior in a checkout flow step, as it only affects how data is passed between subflows, not how screens are displayed or rendered. Editing the default subflow directly is not a valid way either, as it can cause conflicts or errors with other stores or environments that use the same default subflow. Adjusting next-state in previous subflow configuration is not a valid way either, as it only affects how subflows are transitioned or navigated, not how screens are displayed or rendered. Salesforce

Reference: B2B Commerce Developer Guide: Checkout Flow, B2B Commerce Developer Guide: Checkout Subflows, B2B Commerce Developer Guide: Customize Checkout Steps