How to create a View Cart button
The view cart button requires a different kind of code than an add to cart button.
On your PayPal account, edit one of your existing Add to Cart buttons.
You will notice below the button code there is a "Create a View Cart button" link.
Click on the link to create the code you will paste in the View Cart button of your website.
Watch the tutorial video:
How To Add PayPal Buttons