Get your taxes done using TurboTax

The distribution you took last year and choose to pay taxes on it over 3 years   then that section of the 1099-R interview is not yet functional so you cannot correctly file the return now if you have 1/3 of the 2020 distribution to report in 2021 you still have to wait.

Once those forms are implemented you will visit the "Retirement" topic in the "Wages and Income" tab.  If you have Forms 1099-R for TY2021 distributions, you can enter them as usual. 

If not, you just select "NO" when asked if you received a 1099-R. 

At either point, you will then be asked about prior year "Disaster Distributions."  Follow the prompts from there to enter the second installment of your distribution.