What you do with the proceeds of selling your house has been irrelevant since 1997.

SALE OF HOUSE

If your gain was more than  $250,000 filing Single, or more than $500,000 filing Married Filing Jointly the sale must be reported on your tax return.  Whether you re-invested the gain in to another house is irrelevant.  If you  have a Form 1099-S go to Federal>Wages and Income>Less Common Income>Sale of Home (gain or loss)

If you owned and lived in the home as your primary residence for at least 2 of the last 5 years on the date of the sale, you do not have to report the home sale if the gain is less than $250K filing Single, or less than $500K filing Married Filing Jointly (and you both owned and lived in the home for at least 2 years).

• If you are using online TT, you need Premier or Self-Employed software to report the 1099-S
• .https://ttlc.intuit.com/questions/1901135-i-sold-my-home-at-a-loss-is-this-deductible

There is no way to show and handle the step-up value when selling your primary residence. I know

I am entitled to the step-up as of the date of my wife's death in 2012. Turbo Tax has no way to handle

that. I'm using 2012 Premier. Any suggestions?

2012 Premier?  What are you trying to do?  2012 is no longer supported; it cannot be updated.  If you need to prepare a 2012 return you should seek a paid tax pro's help.