There are two general-purpose buttons for the Shipping Page: Return to Cart and Submit Order. You should have both of these buttons in your template. You can place them in any location that makes sense to you, and you can have more than one instance of each button.
Each button has a unique CSS class. Beyond that, you may want to wrap the buttons in an HTML table cell or a span to apply additional formatting, such as white space around the buttons.
|input.button68||The "Return To Cart" button.|
|input.button67||The "Submit This Order" button.|
|input.button62||The "Confirm" button if the Confirmation page is enabled.|
This example puts the buttons inside table cells and defines CSS attributes for the td.buttons selector.Next: Confirm Required Tags