Understanding Requests in Python

My friends and I want to build an app in Python using the Twilio API and Yelp API with no experience in building web apps.

The app follows the idea that we get a zip code from a user from Twilio and Twilio sends the zip code to the Yelp API to find the first listing of a book store and returns it to the user.

What do we need to know to accomplish this? How would we retrieve the zip code and send it to the yelp api. (ie, storing the zip code in a variable, putting the app online)