Added installation steps in the readme file.

README.md

@@ -1,3 +1,56 @@
 # CKEditor 5 keyboard marker
 
 This plugin adds support for the keyboard input element (`<kbd>`) to CKEditor 5.
+
+![Keyboard marker example](assets/demo.gif)
+
+## Installation
+
+* Follow the [Creating custom builds](https://ckeditor.com/docs/ckeditor5/latest/builds/guides/development/custom-builds.html) guide.
+* Execute `npm i @mlewand/ckeditor5-keyboard-marker --save` (or `yarn add @mlewand/ckeditor5-keyboard-marker`)
+* Include the `Kbd` plugin and add `kbd` button to the toolbar (if desired).
+
+An example configuration:
+
+```js
+'use strict';
+
+// The editor creator to use.
+import ClassicEditorBase from '@ckeditor/ckeditor5-editor-classic/src/classiceditor';
+
+import EssentialsPlugin from '@ckeditor/ckeditor5-essentials/src/essentials';
+import AutoformatPlugin from '@ckeditor/ckeditor5-autoformat/src/autoformat';
+import BoldPlugin from '@ckeditor/ckeditor5-basic-styles/src/bold';
+import ItalicPlugin from '@ckeditor/ckeditor5-basic-styles/src/italic';
+import HeadingPlugin from '@ckeditor/ckeditor5-heading/src/heading';
+import LinkPlugin from '@ckeditor/ckeditor5-link/src/link';
+import ListPlugin from '@ckeditor/ckeditor5-list/src/list';
+import ParagraphPlugin from '@ckeditor/ckeditor5-paragraph/src/paragraph';
+import RemoveFormat from '@ckeditor/ckeditor5-remove-format/src/removeformat';
+
+import Kbd from '@mlewand/ckeditor5-keyboard-marker/src/Kbd';
+
+export default class ClassicEditor extends ClassicEditorBase {}
+
+// Plugins to include in the build.
+ClassicEditor.builtinPlugins = [
+	EssentialsPlugin,
+	AutoformatPlugin,
+	BoldPlugin,
+	ItalicPlugin,
+	HeadingPlugin,
+	LinkPlugin,
+	ListPlugin,
+	ParagraphPlugin,
+	RemoveFormat,
+
+	Kbd
+];
+
+ClassicEditor.defaultConfig = {
+	toolbar: [ 'heading', '|', 'bold', 'italic', 'kbd', 'removeFormat' ],
+
+	// This value must be kept in sync with the language defined in webpack.config.js.
+	language: 'en'
+};
+```