link go to specific screen

Hi Guys,

If I remember correctly, some time ago someone placed an example of how to prepare a solution which allow us to visit a specific screen using a specific link. For example, if I use www.link.com?category=1 I go to the first slide of course, if category=2, I go to the second etc. I know how to do that, but also review some examples would be helpful for me (maybe there are better solution than I'm having in my mind).