How do I get to last years return?

If you are asking for the 2017 AGI-

If you filed with TurboTax or have an original copy of the 2017 tax return, check here  2017 AGI.

Or 

The best and fastest way to access the 2017 AGI is to order a transcript from the IRS.  Click here  Get Transcript  and select "Get Transcript Online " On the transcript, look under section "Adjustment to Income" and find the amount for Adjusted Gross Income.