BindTuning themes include a set of custom page layouts designed for use within Classic SharePoint sites. By default, these page layouts are automatically installed into your site's Page Layouts and Site Templates gallery if the SharePoint Server Publishing Infrastructure feature is active during theme installation.
If your theme's page layouts were not automatically installed, you can manually provision them by following these steps.
Navigate to Site Settings > Site Actions > Manage site features;
Locate "SharePoint Server Publishing" in the list of features.
If it is not active, click Activate.
Wait for the page to refresh completely before proceeding to the next step.
Navigate to Site Settings > Web Designer Galleries > Solutions;
Locate the theme solution.
Click on the solution name, then select Deactivate.
Wait for the page to refresh and confirm the status changes to "Deactivated".
Activate the theme solution again.
Wait for the page to refresh completely.
The page layouts should be installed and available in your site's Page Layouts gallery.