We replaced our ancient system with a cart.
You can add the products you chose to your cart and, before paying, you will be able to correct your order if necessary. This will allow you to buy several things with only one transaction.
When you check out, you will be redirected to a page explaining how you are going to receive your products.
They will be sent you by e-mail, using the e-mail of your PayPal account.
If you have any problem receiving or opening the documents, please let me know.