The free Thanksgiving lesson is here: https://answersingenesis.org/store/product/abc-thanksgiving-lessons/?sku=90-4-085

You'll need to add it to your cart and go through the checkout process. (You won't need to provide any credit card information unless you have something else in your cart.) I recommend logging into your account before you check out, as that will allow the free downloads to be immediately added to your Answers in Genesis account.