Polish readme

headless/README.md

@@ -1,5 +1,31 @@
 # [![xterm.js logo](logo-full.png)](https://xtermjs.org)
 
-⚠ This package is a work in progress
+⚠ This package is experimental
 
 `xterm-headless` is a headless terminal that can be run in node.js. This is useful in combination with the frontend [`xterm`](https://www.npmjs.com/package/xterm) for example to keep track of a terminal's state on a remote server where the process is hosted.
+
+## Getting Started
+
+First, you need to install the module, we ship exclusively through npm, so you need that installed and then add xterm.js as a dependency by running:
+
+```sh
+npm install xterm-headless
+```
+
+Then import as you would a regular node package. The recommended way to load `xterm-headless` is with TypeScript and the ES6 module syntax:
+
+```javascript
+import { Terminal } from 'xterm-headless';
+```
+
+## API
+
+The full API for `xterm-headless` is contained within the [TypeScript declaration file](https://github.com/xtermjs/xterm.js/blob/master/typings/xterm-headless.d.ts), use the branch/tag picker in GitHub (`w`) to navigate to the correct version of the API.
+
+Note that some APIs are marked *experimental*, these are added to enable experimentation with new ideas without committing to support it like a normal [semver](https://semver.org/) API. Note that these APIs can change radically between versions, so be sure to read release notes if you plan on using experimental APIs.
+
+### Addons
+
+Addons in `xterm-headless` work the [same as in `xterm`](https://github.com/xtermjs/xterm.js/blob/master/README.md#addons) with the one caveat being that the addon needs to be packaged for node.js and not use any DOM APIs.
+
+Currently no official addons are packaged on npm.