So I re-downloaded the file and tried to upload the theme to the site. For the cian.zip I got the error message:
Unpacking the package…
Installing the theme…
Destination folder already exists. /home/legaci/lifestorageapp.com/wp-content/themes/cian/
Theme installation failed.
For the other zip file, themeforest-ItY62wKn-cian-app-landing-page-wordpress.zip, I got the error message:
Unpacking the package…
Installing the theme…
The package could not be installed. The theme is missing the style.css stylesheet.
Theme installation failed.
Do I need to delete the original theme in order to reinstall it? Is there no other way to update it?