Roth IRA

I want to contribute to a new Roth IRA.  For this year 2021 and last year 2020.  I do not have an Ira yet and I am 51 years old.  I can contribute $7500 for both of these years correct, cause I am behind.  Can I contribute more for past years?

Now as a business owner, I have to pay myself w-2 wages to be able to contribute in the future and moving forward correct?