There is no content on the booking form, checkout page, confirmation page, or other BuddyClients page.
If you have selected the page manually, ensure the correct shortcode is included in the page content. The shortcodes are specified in the Pages tab of the BuddyClients settings. In your WordPress page editor, add the shortcode block and paste the shortcode into that block.
If you use the “Create Page” buttons, the shortcodes will be inserted automatically.