1. How to configure
To get a UPS account you need to configure your account on https://www.ups.com/upsdeveloperkit?loc=en_PL
After that you need to request for an access key. It's very simple process.
2. How to use it
Go to [Sales/Shipments] to generate your first packing slip. Click the “View” button in specific shipment (you need to create one).
You will see new button in the top of the screen “Generate UPS Packing Slip”, click it:
You will see the entire packing slip generator form.
You need to fill the whole required fields to generate packing slip.
Note that UPS plugin is validating many entered fields.