After the PODs have been loaded you will see the Linked POD in the POD Bin

You can now drag the Linked POD over to the template you are creating and see the information in the Parent "LinkedPOD" is now visible in the child template

If you would like to change the contents of the LinkedPOD, open the Parent Template and change it's contents.  

Then return to the child template and output the child template. The Outputed document will show the information from the updated parent template (Note: For this to work the child template must be connected to a data source).