Creating new PHP Page

I like to create a separate php page where I will add things that I want to go in the side bar (tag-ads-community links etc).

So I will only add on the theme sidebar:

<?php separatephp(); ?>

Any help how to create a code for separatephp? Like the command so sidebar will pull data on this.

I will apppreciate any help on this.. if you know site that can help..please post too.. thanks!