How do i import past years tax return info into this year turbotax for history. I had to change to a different computer with 2018 turbo tax deluxe

last two years I used turbo tax on an old computer. this year I have installed Turbo Tax deluxe on a new computer. I followed to steps to try to access my returns online without success - 2015 and 2016 were filed through turbo tax. How do I access these?