From Wikigogy

I created Template:Cathelp to make it easy to put some standardized help info at the top of category pages. --Roger 04:41, 11 April 2006 (UTC)

Put {{cathelp}} at the top of a Category's text field to include the category help text there.

Template within a Template

Template:Cathelp also contains the Template:Wg that says what our wiki is for and invites folks to jump right in. It is quite alright to include templates within templates like this but don't do so unless you feel it really does simplify things. In most cases it is probably more straightforward and simpler to just type the full text of whatever you want in a single template instead of having a template that contains another template.