Another way you can create a Work Order within a Work Order is by using the Create New WO button on the module toolbar. This will create a new, empty work order that is linked to the current work order in the Related Work Orders grid (in the Related tab in the Standard Work Order module). This is useful when you want the current work order linked to the new one, but you don't want any data carried over into the new one.
How To Create a Work Order within a Work Order Using the Work Order Toolbar
Note: You must be in View mode for this button to be enabled.