How do I file 2020 taxes using 2019 income amounts???

You don't use 2019 income amounts to file a 2020 return ... you must use the 2020 income.   

NOW when you get to the EIC section, if you are eligible,   then you will be given the chance to use the 2019 earned income figure instead of the 2020 figure to see if the EIC credit is higher.   Read those screens carefully ... if it is not helpful then back up and say no this time.  

I didnt get asked that questions. I had earned income and unemployment in 2019 and unemployment in 2020. I have a qualifying child. 

If you have not filed yet then go back to the deductions & credits tab and complete the EIC section you missed the first time thru.  

If you have already efiled and the return is pending IRS acknowledgement....

If you have already filed and the return is pending it is too late to make any changes  UNLESS the return gets rejected ... then you can make any changes needed and refile. 

Can I change my return if I already submitted it and you’re holding it until the IRS opens?

No. Once you submit your return, it’s considered to be in pending status. We’ll hold all returns submitted before the IRS opens and submit them when the IRS is open.  Processing of returns is expected to start on or about 2/12 however some returns may be pulled earlier in test batches so watch your email for alerts. 

Once the IRS either accepts or rejects your return:

• If your return is accepted: If you want to change your return, you’ll need to amend it AFTER the original return has fully processed an you have the original refund in hand or have paid the original balance due.
• If your return is rejected: We'll send you an email to notify you, along with instructions on what to do. You can then open your return and make any changes you would like. Just be sure to fix the reason the return was rejected as well.