Hi @jonespossibly,
There were a lot of changes in v3 of the SDK introduce Webpack and to mitigate the amount of additional work, so some older guides will likely include all the additional steps for tsconfig.json and pbiviz.json that you needed to make dependencies work previously.
You're best loading as much as you can via npm so that everything's bundled at build time. Loading libraries over the web can be tricky if the endpoint is not permissive enough to deal with the CORS restrictions in the sandboxed iframe.
npm install [package] --save-dev is sufficient to make sure that your project has the dependency.
Webpack will bundle what you import in your source (providing there's a loader for it). With libraries that support TypeScript, this usually just works.
You can probably take a look at any of my production visuals on GitHub to get an idea of what the key files might look like - these all seem to be okay with just loading via npm and Webpack handling the imports via the usual build process.
Bootstrap can be installed via npm, but it uses sass (the SDK uses less) - therefore you're need to load the distribution .css file in your main visual entry point, kind of like this (I have used it previously, but don't think I ever put one into production, so I don't have any source I can link; the principle is the same though).
Last time I used Bootstrap, jQuery was it was optional, depending on whether you wanted to use the dynamic stuff or not (I think we also had to install popper.js on older versions for tooltips etc., although it looks like it might be streamlined now to just the bootstrap package). Although, if you specifically want jQuery, then it's best to install it via npm separately so that you get the version you want.
Regards,
Daniel
