Most of the configuration of the Shopping Cart is done through its Behavior Editor / Settings / Options

While there are a range of settings here which you may wish to adjust for your circumstances, the defaults will work fine, and all you need to do is:

• Set the 'Continue Shopping Target Link' to point to the 'Products Listing' page
• Configure a method of payment in 'Payment Processors'.
  For simplicity, choose PayPal 
  • Set 'Enable' to True.
  • Enter the email address of your PayPal account.

And follow these instructions to make a couple of configuration settings to your PayPal account itself.

In use, the cart will look like this: