I think there is a step missing here somewhere, @TW_Tones. While the Template:Navbox - MediaWiki template which I linked to before is considered to be a meta-template, it isn’t the one that will ultimately get transcluded into the actual wiki article content tiddlers. It just creates the general structure for all navboxes. From there, the individual navboxes themselves are created as separate templates, such as Template:Global templates nav - MediaWiki which will then get transcluded to the bottom of every article (tiddler) which is listed in that template. For now though, I am just working at the meta- level, creating the general foundation for all navboxes.
Example from MediaWiki
If you have a look at the source of the Template:Global_templates_nav example linked above, you’ll see that it invokes the Template:Navbox template. Meanwhile, the Global templates/Proposed specification, short version - MediaWiki article invokes just the Template:Global_templates_nav template, which uses the Template:Navbox template for its basic structure.