"do I put the total from my 2019 and 2020 contributions in the total 2019 box and put the 2020 contributions in the box that states between Jan 1 2020 to July 15 2020?"
Yes, you put the total of your contributions made for 2019 in the first box but only those contributions made in 2020 for 2019 in the second box. This agrees with what you have described for the amounts to be entered in each of the boxes. These entries correspond to Form 8606 lines 1 and 4 (for those who are required to file Form 8606 because they made nondeductible contributions).
