I can add it to the stylesheet of my child theme. But do I write an entire new part or can I take something out of the parent stylesheet? If not, what do I add to the Child stylesheet and how do I connect it to my current more tag?
The Developer Tool is only supposed to expose the HTML and CSS.
You shouldn’t need to go looking for the CSS in the original stylesheet.
You should instead go forth and create new styles from that information you received when the Developer Tool exposed HTML and CSS.
Post here the CSS you’re trying in your Child Theme style.css file if it still doesn’t work.