To connect your Etsy store to ShipStation, simply follow the steps below.
Head to your Account Settings (the wrench icon in the upper right).
Next, select Selling Channels and then Store Setup from the sidebar on the left.
On the page that appears, click +Connect a Store or Marketplace.
Select Etsy from the list of stores.
Now, log in to your Etsy admin panel. Your Etsy username will be in the URL for your user settings. To locate this, click on a store from the lefthand sidebar.
Next, click on the You dropdown and select View profile.
Your username will be at the end of the URL for the View Profile page.
It may alternately be displayed like
You'll now see your listed Shops. Here, select the store you wish to connect.
Click Connect and you'll be sent to log into your Etsy account. Login, then click Allow Access to authenticate ShipStation's connection to your Etsy account.
Finally, you'll be sent back to ShipStation and can set up your store settings within ShipStation. You'll need to enter in your company's name, phone #, e-mail, website, and logo, in addition to choosing which e-mail templates and/or packing slips to use for the store. Finally, you'll choose how you want your products to be imported (by Name or by SKU). If you don't know all of this information, you can always go back and change the information after you set up your initial connection.