Substitution templates will be correctly used in the future. Templates will be slowly making the switch from substitution to regular templates.. Visit each template page for documention on usage, examples, and blank code.
Substituting Templates is an easy way to add the structure of the appropriate page to the page you are creating. Using a Substitution Template also automatically adds some of the correct Categories to the page you are creating.
Just add the following to any page you are working on, publish your changes, and then edit again to see the structure added and ready to be edited.