Hello, Dim,
Thanks for contacting us.
Please read our docs – https://www.8theme.com/documentation/xstore/theme-installation/theme-package/ and watch video – https://youtu.be/4n1re0jKorc
It looks like you are trying to install a wrong archive (full package instead WP theme only). Or you did not check requirements – https://www.8theme.com/documentation/xstore/theme-installation/xstore-theme-requirements/
Read this article also – https://www.wpbeginner.com/wp-tutorials/how-to-fix-the-link-you-followed-has-expired-error-in-wordpress/
Kind Regards,
8theme team