I uploaded a new "Ancestors of Randy Seaver" Family Tree last week, and over the past several days I have attached some historical records (census records) to persons in the tree. Here is the Family Tree Pedigree View of my tree:
Just above the dark green header, on the right side, is the link for "Tree Settings." Click on that link, and you see your "Tree Info" and over on the right side is a section for "Export your tree" with a light green button for "Export tree." Click on the light green button, and Ancestry will prepare your GEDCOM file for downloading:
When the GEDCOM file has been created from your database, then another light green button that says "Download your GEDCOM file" appears:
Click on the "Download your GEDCOM file" and the box asking if you want to Open or Save your file appears:
If you want to Open the file in your genealogy software, then click on "Open." If you want to save your file to your file folders, click on "Save," and you can open the GEDCOM file later using your genealogy software. You can also Cancel at this point too.