If you haven't yet, visit the Terminology section for a quick note on what we're considering a patron, restaurant, ordering page, and more. This guide is growing and we hope to answer more of these questions as it does.
To start, be sure you have your token from the Authentication endpoint.
The Menus endpoint will return all menus that are available to you, when logged in, at all Restaurants that you have attached. This data is very large and cached, so to mitigate slowness issues, we suggest unpacking this on the front end using the restaurant_id key in a given menu object into related buckets.
You can then use the Ordering Pages endpoint, you will be able to grab the menus that you need based on fulfillment method. You can use the Fulfillable Menu Items to determine what is and is not available at any given time. Visit the respective endpoints for more information on what is exposed in the JSON to determine what to show and when.