The advanced tab of the configuration screen has an expancing checkout area where the checkout flow can be set. This page described the guided flow. 

When a visitor proceeds to legacy checkout they see the following:

• Optional Cart Header: This can be a formatted text string entered in the advanced tab, or it can be a container from elsewhere in the site.
• A registration subscreen:
• User Information Collection: This is a ship-to form or a visitor registration area.
• Review screen with Promos, Shipping Options, and Editable Order Summary: This is a list of what was ordered with links to edit the items and a total including promotions.
• Payment screen: This will include a Payment system message if enabled.
• Confirmation Screen: Includes a list of the order, shipping, and payment state.

Rather than trying to make these all fit and flow in a single screen the guided flow breaks these into subpages with a clickable progress bar that allows pre-view of next steps or adjustments to prior steps.