Click 'Products' in the 'Creatives' tab. This section contains a list of your joined advertiser programs that have product feeds. On the left side of the page, you may filter by 'Advertiser', 'Advertiser Category', and 'Keyword'. After setting a filter, you can select 'Download Feed' in the right hand corner. If you prefer to download all product feeds, do not select any filters and simply use the link provided at the top of the page.