This engagement app simply allows you to create a custom HTML page for publishing on a Facebook page.
Paste in fully de-bugged HTML, CSS, and JS code to customize the look of the page.
Note: This is an advanced feature! Your code will not be fully 'error checked' here. So be sure to paste in code that has been fully debugged first.
Preview, publish and deploy the engagement app
See the section "How to preview, publish and deploy an engagement app" for details.