See the component page for updated information information.
The easiest way to install the component in your page is by using bower:
bower install p5-element
Include the component and webcomponentjs on top of you page:
<script src="bower_components/webcomponentsjs/webcomponents.js"></script>
<link rel="import" href="bower_components/p5-element/p5-element.html">
Simply use html tags in your code. It will render the editor with the canvas.
<p5-element></p5-element>
Since the element encapsulates p5.js functions and runs in instance mode, you can have multiple elements in the same page and run them side by side.