You will need to extract the downloaded .zip file somewhere on your computer. Inside those files should be another .zip file with the theme name… upload that one into WordPress.
If none of them are working then it’s definitely an error in your process. When you extract that file to your computer, what is the name of the .zip file inside which you’re trying to upload?
Sorry about not responding, so the unopened folder is named.- themeforest-15785425-barch-architecture-portfolio-wordpress-theme-file-and-license20180831-18132-ceqn62.zip
the opened folder is named - themeforest-15785425-barch-architecture-portfolio-wordpress-theme.zip