You must have a manual store set up in your ShipStation account where BackerKit is to send orders. ShipStation includes a manual store in your ShipStation account by default. If you have deactivated it or would like to create a new one, follow the instructions on adding a manual store in our Connect a Store article.
If you need to enter a GUID (Globally Unique Identifier) for your store into your BackerKit account, locate this in ShipStation by clicking the Edit option next to the manual store in
Settings > Selling Channels > Store Setup. The GUID is the set of numbers at the end of the URL that appears in your browser's URL field.
For details on how to configure your BackerKit account, review their article How do I integrate with ShipStation.