Hi, I’m new to Discourse and really love it’s features and function. I’m wanting to heavily customize it’s appearance and the way it presents content. I’ve been reading through various threads and posts trying to understand it. I have javascript coding experience, but I’m getting confused. By heavily customized I mean: removing the sidebar, adding navigation items to the top bar. Displaying topics with the author name, avatar, subject, and preview text, along with most recent reply and a preview of the reply with the reply authors avatar and name. Topics grouped under categories in one big list of categories and their topics (old school). I guess I need to get my head around how to override the data that gets displayed, or fetched then displayed, and I’m confused on how to best do that. Would it be a single “theme” would it be a theme component? Would it be a plugin? Would it be multiple themes, components and plugins? What’s the difference between a component and plugin? I wish there was a youtube video showing the development of a heavily customized “theme” like this. I am currently gathering a list of “addons?” that do similar things to what I want to achieve and am trying to read their code and understand them, but man it’s really confusing coming in to this “fresh off the street”. I learn best by watching videos than I do reading. Any tips, advice, or videos I might haven’t become aware of? Any help is very much appreciated.
Since the changes you want would imply fetching extra data to pages, a theme or a component wouldn’t be enough, you need a plugin to achieve your vision.
Any tips, advice, or videos I might haven’t become aware of? Any help is very much appreciated. 
I have a ton of reading to do. Hopefully it’ll all start to make sense. I found a really relevant topic: