Retirement tax questions

Hi Dmentz,

I have been making backdoor Roth IRA contributions (converting nondeductible/after-tax traditional IRA contributions) since 2018.  

For 2018, i made $5,500 contribution in early 2019.  since i contributed in 2019, I didn't receive the 1099-R for $5500 for 2018 so i forgot to file for 2018.

For 2019, i made $6000  contribution in early 2020.  I received 1099-R $5500 for 2019 but i forgot this contribution was for 2018 and i filed for $5500 for 2019.  But the $6000 contribution for 2019 was not filed.

For 2020, i made $6000 contribution before end of 2020.  Since i made $6000 contribution in early 2020 for 2019 and another $6000 end of 2020 for 2020, i received 1099-R for 2020 for $12,000.

How should i make the correction in Turbo Tax to reflect the correct contributions for each year?

Thanks,

Vincent