Getting started guidance

Sorry to post here, but no response from the IRC channel, and you do not seem to have a Gitter or anything like that. This is more of a getting started question. Studying the demos, it seems to me as though the required bits, jquery, etc, are all included in the overall jquery-ui package as a bundle? There is no need for me to download those separately? Additionally, studying the examples, if I just follow that pattern, i.e. include the require script, then bootstrap script, and any warming up, UI initialization, etc, goes in the bootstrap script include? As contrasted with previous versions where I might have a $(function ...) initializing the bits in my jquery based pages? As far as themes, adding the packages from Node npm sources, all I get are the base theme. If I download those separately, I just refer to those CSS bits accordingly? In other words, that is all seamless? Thanks!