Add usage and documentation sections to README

README.md

@@ -7,6 +7,37 @@ A 3D math library for Wowser.
 
 Licensed under the **MIT** license, see LICENSE for more information.
 
+## Usage
+
+To install `wowser-math`:
+
+```sh
+npm install wowser-math
+```
+
+To use `wowser-math` in an ES2015 module environment:
+
+```js
+import { Matrix4 } from 'wowser-math';
+
+const matrix = new Matrix4();
+
+matrix.scaleByNumber(4.0);
+```
+
+## Documentation
+
+`wowser-math` ships a complete set of jsdoc documentation.
+
+To build a local copy of the documentation, check out the `wowser-math` repo and run:
+
+```sh
+npm run doc
+```
+
+A documentation directory will be created at the root level. The documentation can be viewed in a
+web browser.
+
 ## Compatibility
 
 Wowser Math should work with any browser that has native support for: