Get your taxes done using TurboTax

so what your saying is to get the money owed to me I need to file in order?  If I file 2019 now I can never go back and file 2016-2018 and get my refund/child tax credit?

My ex husband was court ordered to show his tax returns for 2016-18 so that I can be certain not to be audited like in 2015. So in 2016 he claimed 2of3, 2017 1of3, 2018 1of3. So is it important to file in chronological order and should I wait and give a certain amount of time in between sending them in? turbo tax stated that I would have to mail in paper tax form for the previous years.