XF 1.5 Staff CSS & Configuration

So, I am not sure how to find the Staff.CSS that this guide refers to. What I want to do is change the banner color of my current 'Staff Member' banner and, move it below their main tag(s). Right now it is above 'Administrator' and 'Owner' which I don't like. Any help is appreciated! Thanks!
You use the EXTRA.css template to override the default styling.

This guide explains how to do custom banner styling: https://xenforo.com/community/resources/creating-custom-user-group-banner-css.2000/

To move elements, you need to edit the HTML templates.
This guide will help with that: https://xenforo.com/community/resources/how-to.4390/
Thanks for a fast reply, but I don't quite see where to look in the second link for help on moving the positioning of banners ETC. My bad if I'm missing it, but could you be more specific on like what to add and where to add it, or point me to where that would be specified? (Which category in Broguide)

Thank you!