Please be advised that after installing/upgrading an app or theme, you might notice an issue that site layouts on several pages will be broken or display incorrectly. It is a very common issue, and you need to Rebuild the Core Theme to apply styles of newly installed app/theme to your site.
In order to perform Rebuild Core Theme, from Admin CP >> Maintenance >> Rebuild Core Theme.
Wait a little bit until the process finished and it will redirect you to Admin CP Dashboard.