A user wants to leverage a three columnlayout on a page.

To leverage a three column layout on a page and move themini-cart widget from the right to the center column, the requirement can be fulfilled by creating a Gross Layout Override. This is a custom Visualforce page that overrides the default layout of a page and allows changing its structure and content. The user can create a Gross Layout Override that uses a three column layout and places the mini-cart widget in the center column. Salesforce References: B2B Commerce and D2C Commerce Developer Guide, Gross Layout Overrides