Just to clarify, your Instructables Inbox is for PM's (Private Messages) sent by members within Instructables only. It is not associated with any other mail system. If you are logged in and your Inbox shows "0", its because you have no mail.
Login and click on "You" then the "Settings" tab and then "Email Alerts" and set how you want email messages sent. To get something in your inbox, someone has to send you message.
PDF Downloads As a Pro member, you will gain access to download any Instructable in the PDF format.
You also have the ability to customize your PDF download.
To get something in your inbox, someone has to send you message.