If you look in the Admin panel you can find a section called Publishing, containing Facebook and Website.
To place the "See MENU & Order" button on your website, you need to copy the HTML code (which you find in the Admin panel > Publishing > Website) and paste it in the HTML source code of a page on your website. If you are not the creator of your website, then please ask your website administrator to help you out with this. It should only take a few minutes.
Make sure your button will be visible from your main homepage. For example, we have seen the button placed only at the bottom of contact page which significantly diminishes the chances of getting any online orders.