I'm including instructions on completing your 2016 return (now considered a prior-year return).
https://ttlc.intuit.com/replies/4186197
If you've already made payment for the 2016 Premier program, you can contact TurboTax Customer Support during business hours to request a download of the software you've purchased. See the instructions below on contacting Support.
https://ttlc.intuit.com/replies/3300041