I don’t know, am I stupid?

I have been working on a new site using wordpress and have made a custom plugin to deal with a few things like a custom search etc… I have managed to get the admin working correctly and additional data to output in to posted pages but for the life of me I can not work out how to call the plugin directly… For instance…

If i have a category in my site under broadband… the url would be /broadband/… If i have a page under this it would be /broadband/post-name/

So, how the hell do I call the plugin manually? I am using All In One SEO pack… Would this be something like /wp-content/plugins/plugin-name? or maybe /plugin-name?

I have not got a clue, so if any of you can help me, thanks a million :D.

Thanks guys.

Marc