Any examples of Craft Commerce checkout process for PayPal or any other gateway? I'm unable to find much documentation nor examples for how to actually utilize Craft Commerce and successfully convert a cart to a completed order.  Any help would be greatly appreciated!
Craft Commerce ships with a templates/shop folder that has a working check-out processes using the Dummy gateway adapter and some default products that get populated during installation.

After installing it, you'd access it by going to yoursite.com/shop.  You can use a test credit card number like 4222222222222 to complete checkout and convert a cart to a completed order.