How come the hide on this template wont appear when it's the exact same as this template?
Because you were using the obsolete class="collapsible collapsed"
format, which requires custom Javascript to work - Javascript that you didn't have installed (but they did).
I updated it to the new class="mw-collapsible mw-collapsed"
format which requires no such JS. See Help:Collapsing for more info.
Thank you! How do you edit Javascript?
Well, there's a few pages, such as Mediawiki:Wikia.js, Mediawiki:Monobook.js, Mediawiki:Common.js, where you'd put code. As for how to make code, well, there's whole college courses on that sort of thing. You might be better off copying scripts from c:dev... lord I barely know how to write the code.
Please note that you do NOT need to have collapsing Javascript installed if you use the non-obsolete form of collapse code.