Clicking an Order button will add one item to your PayPal shopping basket and take you to the Paypal page where you can see exactly what you have ordered.  If you want to order more than one of any item you can change the quantity on the shopping basket page.  If you change your mind you can delete items from the shopping basket page at any time before you check out.

Clicking the View Basket button will take you to your Paypal shopping basket without adding anything else to it.

You can add as many items as you wish to the shopping basket and check them all out at once.  Shipping charges will be added when you check out and you will be prompted to enter the delivery address.