How do I add a custom routed command in WPF?

I have an application that contains Menu and sub menus. I have attached Appliocation Commands to some of the sub menu items such as Cut, Copy and Paste.
I also have some other menu items that do not have application commands.
How could I add a custom command binding to those sub menu items?
I have gone through this article but unable to attach event to my sub menu items.