Select the appropriate check box to set the way you would like to use the shopping cart. Choose the second check box if you want to be able to select all items and then view the shopcart summary. In this case, any previous item in the shopping cart is discarded
Choose first check box if you always want the system to take you to the summary shop cart whenever you select a new item. In this case, the system keep tract of any previous items you have in the shopping cart

(1) Choose all items before shopcart summary

(2) Display summary after selecting an item