This template merely converts the SMW #show parser function into a template. It allows you to quickly and easily find out any one detail that we have in our database. For instance, if you wanted to figure out who were the 3D artists on Last of the Time Lords, you would just type:
{{show|The Girl in the Fireplace (TV story)|3D artist}}
The following would result: Mark Wallman, Chris Petts, Matthew McKinney
Where a redirect exists, you may freely drop the dab term. So you could instead type:
{{show|The Girl in the Fireplace|3D artist}}
Since correct operation of the template depends upon getting the story name precisely correct, however, you are better off using the dab terms. Every television story's "proper" title has an appended (TV story), which means you will always be correct to use that form of the name. But you will not always be right dropping the dab term. For instance you must use 42 (TV story) since 42 doesn't exist, and you must use The Five Doctors (TV story) since The Five Doctors is actually a page about an in-universe video game.
Equally, you must be sure that the property name is precisely correct. So you'll want to consult Special:Properties for a full list.