First, log in to 3dcart and click Modules in the lefthand sidebar.
Click the + icon on the REST API row.
Click the Change Settings button that appears.
On the REST API page that opens, click the + Add button in the upper righthand corner:
Enter 9ff5a12b310ec4ea9d22666ecaf249d8 into the "Public Key:" field that appears and click + Add.
In the popup, select + Authorize.
A new ShipStation popup with the 3dcart modal will now appear.
(Note: If no popup appears, make sure to disable any popup blockers on your browser).
Select your Product Weight Units from the drop-down menu and click Connect.
Your 3dcart store is now updated!
ShipStation will open in a new tab where you can further customize your store's information!