You must be a new subscriber, WELCOME TO SCANPOWER.  The first thing you need to do when using ScanPower is link your ScanPower and Amazon Seller accounts.  The first time a user clicks on LIST they are directed through the "MWS pipeline" to link the accounts.  This is going to take you to Seller Central where you will need to log-in and the system will guide you through the process.  Once that is completed you can set-up your DYMO without issue.