Ways to incorporate external JS libraries

Even though I have used so many external libraries, I feel like I’m always fumbling through the download/install process and decision making. Can someone check my understanding of the different ways to incorporate an external JS library into my own JS project?

Option 1 - Download the min file to project folder and reference it in the index.html page within <script> tags.

OR

Option 2 - install via npm (which has to already have been installed via the node.js install process) or other package bundler (like yarn??)

Is that it…? What are the caveats and/or best practices around deciding which one to use?

Thanks!