A shopping cart will appear at the bottom of the page when it refreshes. You can adjust the quantity and press enter: the shopping cart will calculate the price.
If you want to add another card click under that card and it will be added to the shopping cart, again you can adjust the quantity.
When you have finished click on “check out with PayPal”. The order summary will open on a new page where you can choose to pay with a PayPal account or with a debit/credit card.