Order Button not showing up on every page
Whether or not the Order Online! button shows up on each of your web pages depends on how you add it to your website (and how your website is built).
If your website has a template that applies to all pages, when you copy and paste the Open Dining code to your website, it will show up on every page.
If you have front-end pages on your website that are just static pages (no framework or anything), then you have to open up each page (home, pricing, features, etc) and copy/paste the Open Dining code.