Retirement tax questions

Thank you ... I'd like to clarify, so even though almost all of the earnings took place in CY2020, I will assign those earnings to my 2019 taxes, is that right?

Also, I was under the assumption that I needed to amend my 2019 taxes by Oct 15 2020 ... it sounds like that is not the case, and I will have to wait until Jan 2020 at the earliest to amend, is that correct?