how to show breadcrumbs only on subpage?
If you are using Drupal 7, then you can use:


Path Breadcrumbs 
Context path breadcrumb



  Path breadcrumbs module helps you to create breadcrumbs for any page with any selection rules and load any entity from the URL!
  
  





  This is a plugin module for the context module. It takes the request URI part of the URL of the current page (for example /our-company/our-team/steve) and uses this path to build the breadcrumbs.