1. A Tour of Google Cloud Hands-on Labs introduces the Google Cloud console. There's also a walkthrough on how to enable an API (e.g. Dialogflow).
Google Cloud Project refers to the entity that contains the cloud resources and services (e.g. pool of virtual machines, databases, network, settings and permissions)
Basic Roles/Primitive Roles (Viewer, Editor, Owner) are highly permissive and are not recommended in production environments. Instead, use predefined roles or custom roles.
The core principle of REST architecture style is to "define named resources that can be manipulated using a small number of methods."