The file you have download is the theme package zip file where include professional-pro.zip, xml file, sql file, installation guide and theme documentation so when you finish the download just extract the theme package and you just need to upload professional-pro.zip file in the WordPress.
If you still facing the issue then kindly send us the site URL and the login details to our support email so we can install and setup the theme.
The file you have download is the theme package zip file where include themename-pro.zip, xml file, sql file, installation guide and theme documentation so when you finish the download just extract (unzip) the theme package on your desktop or laptop and then you just need to upload themename-pro.zip file in the WordPress.
If you still facing the issue then kindly send us the site URL and the login details so we can install and setup the theme.