I want to automatically have a template used for a specific namespace so that when the edit page is generated for the first time, it already has some text in it: {{Template| | | | }}. What is the best way to do this?

I also want to customize what a blank page looks like for a specific namespace to allow the user to choose from a list of categories to put the page in, which will then automatically be put in the edit page. How should I go about this?

Thanks!