Category url help

Yes. You can either use a 3rd party job manager theme which supports this already, or add theme support for job-manager-templates (save permalinks after enabling this) and then template the category and job post type archives.

https://codex.www.ads-software.com/Function_Reference/add_theme_support
https://codex.www.ads-software.com/Template_Hierarchy

This would be so much easier with a tutorial.. how long would this take?

Adding theme support takes 1 line in theme functions.php

add_theme_support( 'job-manager-templates' );

I cannot give you a tutorial for the actual theming process – it varies from theme to theme in terms of markup and styling.