Board Thread:Support Requests - Getting Technical/@comment-46181162-20200629190633

I'm trying to get a navbox set up at https://verse-of-the-immortals.fandom.com/wiki/D20_Character_Classes_and_Options for my site. I tried copying the basic navbox instructions from https://en.wikipedia.org/wiki/Template:Navbox and thought I had grabbed all the relevant CSS from https://en.wikipedia.org/wiki/MediaWiki:Common.css but it still comes back with just a placeholder for Body and Header. I'm clearly missing something, but I'm not a programmer and am just about at my wit's end, so if anyone can provide me with a 'For Dummies' version of what I'm missing and what I need to do to fix it, I would greatly appreciate any help. 