Hi, Welcome to Hubpages. When your adding Amazon Affiliate; Click on "my account" at the top next to "start a new Hub," then go to "Earnings" tab, click on "configure" Amazon Affiliate. I hope this helps.
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I would like to share some articles from the HubPages Learning Center regarding the Amazon Affiliates Program. Please be advised that in February, the Amazon Affiliates Program will be changed and included in the blanket "HubPages Earnings Program". HubPages suggests that instead of applying now for the program, you should wait until it is incorporated in the HPE program. Here are the links: