On a tablet or IPAD or PC with less than 15" screen the next step after adding a room selection is not obvious to the user as the "Book now" or Continue button or Cart symbol is not visible unless you return to the very top of the page. According to help via a service request this is because the "banner/header" takes up too much space on the device hiding further selections. Yet on a smaller Android phone the book now stays visible while scrolling and works perfectly.
The Cart symbol or book now button should be visible following user room and rate selection regardless of the device they are using.

At a minimum the IBE should take the user to the top of the screen after selecting a room/rate to make the cart amount and "book Now" button visible to the user. As it is now the user has no idea what the next step is and is more than likely to either click add again or abandon the reservation altogether.