My understanding is
From the way I interpret your post, all (and I mean all) of your understandings are wrong. But hey, it's not like you learn this stuff through osmosis. I know one thing I tell my clients in my computer business is that if you're not screwing something up, you ain't learning anything new.
But when it comes to taxes, mistakes can (and usually will) cost you money. For your situation, this is not the time to start learning. How you do things depends on how you did things on your 2018 and 2019 taxes. as well as your 2020 taxes if you sold a property in 2021. You should (and probably need) to seek professional help for this. Professional help is especially called for if your state also taxes personal income, as getting things wrong on the federal and state return will be a double-whammy for you. The potential back taxes, fines, interest and penalties that could potentially be assessed would make the cost of professional help seem like a pittance in comparison. Please seek professional help for this issue.
