To use this, specify the personal template name (or a shortcut to it) as the first parameter. Next, specify the parameters of the selected template as you would normally. The difference is that you don't need to specify the parameter name, (i.e. you don't need to put |param= for the db-reason template) however, this is made so that you may still do so.
Update: You can now subst: this template; this is, of course, optional.