Firstly, fill your cart with all the items you wish to purchase during that transaction. You'll be directed to the checkout page every time you add a new item - if you want to buy more than one item in a transaction just click the grey "keep shopping" button on the top right-hand side of the screen and shop until your heart's content.
Once you've added all the items you want to purchase stay on the checkout screen.
|Hit "apply coupon code"|
See that line of blue text which says "apply shop coupon code"? Just click on that and a little blank box will open up. Type in the coupon code provided by the shop owner and hit "Apply".
|Type in the coupon code - spelling counts!|
If the coupon code is still in effect (and if you've spelled it properly) Etsy will tell you the percentage that you've saved and then break down the exact dollar amount for you. If you don't see these options then either the coupon code has expired because the sale is over or you've misspelled the code - once you get it right you can hit the green "Check out with Paypal" button and Etsy will walk you through the remainder of the transaction.
That's all there is to it!
Happy shopping & happy stitching J&C