Thanks for asking!
The first thing that you need to test DOTS Address Geocode - US (or any of our other products) is a valid trial or production key for the product. Trial keys are free, valid for 30 days and come with 500 transactions to test with. No credit card is required to sign up for a key.
To get your key, fill out the form on the Address Geocode product page and one will be emailed to you.