Three steps that are necessary to have a subscriber page added to Salesforce B2B Commerce after creating a custom Visualforce page are:
Create a new CC Subscriber Page record that points to your custom Visualforce page. This record will store information about the subscriber page, such as the name, description, URL, and Visualforce page. For example, you can create a new record named MySubscriberPage that points to your custom Visualforce page named MyPage.
Refresh the Page Keys Index in CC Admin. This action will update the page keys index, which is a cache that stores the mapping between the page keys and the subscriber pages. You need to do this whenever you create or modify a subscriber page record.
Enable the Subscriber Page in CC Admin. This action will allow you to select the subscriber page from the CC Page Settings configuration and assign it to a CC Page. For example, you can enable MySubscriberPage and assign it to the Home page. Salesforce B2B Commerce and D2C Commerce Developer Guide,Subscriber Pages