I need to file my 2016 taxes .I have my W2 I just dont know how to use turbo tax since I used it for 2019 and now it’s not letting me to start for a new year

The TurboTax online editions are Only for tax year 2019.

To complete and file a 2016 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2016 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/

A 2016 tax return can only be printed and mailed, it cannot be e-filed.

And so you are aware--even if the 2016 return shows a refund, you will not receive the refund.  You are filing too late for the refund--it has been forfeited.  But if you owe tax due, the IRS wants to be paid.  They will also bill you later for the late fees and interest.  TurboTax will not calculate that.