Single cat page

Hi –
I’m trying to find out if on a page OTHER than the index page, I can just display one cat. I want the main page to display all cats and have navigation to pages that display just one cat with different sidebars than the main page.

Sorry if this is easily addressed or a duh! question, but everything I find discusses how to do it on the index page and I am a complete n00b. Your help is appreciated!