Add advanced usage section to readme for optimizing CSS and JS

README.md

@@ -44,6 +44,38 @@ For the most straightforward development, open two Terminal tabs to execute `npm
 
 Open <http://localhost:3000> to see the page in action.
 
+## Scripts
+
+The following npm scripts are available to you in this starter repo. With the exception of `npm start`, the remaining scripts can be run from your command line with `npm run scriptName`.
+
+| Script | Description |
+| --- | --- |
+| `start` | Starts a local server (<http://localhost:3000>) for development |
+| `watch` | Automatically recompiles CSS as it watches the `scss` directory for changes |
+| `css` | Runs `css-compile` and `css-prefix` |
+| `css-compile` | Compiles source Sass into CSS |
+| `css-prefix` | Runs Autoprefixer on the compiled CSS |
+
+## Advanced usage
+
+Take this starter repository to another level with some built-in addons that you can enable and customize.
+
+### Optimizing CSS
+
+Before you start to use tools that remove Bootstrap styling like PurgeCSS, you can make some broad optimizations by only including the stylesheets you think you'll need.
+
+Look to the `scss/starter.scss` file for your two options of including all of Bootstrap, or a subset of our styles and components. By default we've only imported the stylesheets that Bootstrap requires plus those of the components we're planning to use.
+
+Uncomment specific lines as needed, then recompile to use them.
+
+### Optimizing JS
+
+Similar to optimizing CSS, we publish individual scripts for each of our plugins. This allows you to import only what you need, versus the entire bundle and dependencies. For example, if you don't plan on using dropdowns, tooltips, or popovers, you can safely omit the Popper.js depdendency. Bootstrap 4 requires jQuery though, so you won't be able to safely remove that until v5 launches.
+
+See the `js/starter.js` file for an example of how to import all of Bootstrap's JS or just the individual pieces. By default we've only imported our modal JavaScript since we have no need for anything else.
+
+You can add more options here, or import the entire `bootstrap-bundle.min.js` file, to get all JavaScript plugins and Popper.js.
+
 ## Actions CI
 
 We've included some simple GitHub Actions in this template repo. When you generate your new project from here, you'll have the same tests that run whenever a pull request is created. We've included Actions for the following: