For developer resources and getting started with the platform & API's, please see the below links:
Authenticate to the API; this video and article are focussed on using the API over REST and exploring it with a tool like Postman. For a production deployment it's strongly recommended that you use our official SDKs (and not implement your own REST interface).
Integrate using the API; this article explains how to set up your membership program, the different types of fields and how-to dynamically populate the passes via the API.
You can simply create your free trial account via app.passkit.com and click on "Sign up".