How to duplicate Events, Playlists, Artists, Posts and Custom-Posts

First, you need to install a plugin called "Duplicate Post". 
- Go to WP-Admin > Appearance > Install Plugins > Add New
- Search for "Duplicate Post", install and activate it.

Select Custom Posts you need to duplicate.
- Go to WP-Admin > Setting > Duplicate Post
- Select the "Permissions" tab
- Check all custom posts wanted

A "clone" option is now available below each of your posts.