The Microsoft Power Platform CoE Starter Kit is a collection of components and tools that are designed to help you get started with developing a strategy for adopting and supporting Microsoft Power Platform, with a focus on Power Apps, Power Automate, and Power Virtual Agents.
The Creator Kit helps you create Power Apps experiences on the web and mobile platforms with easy-to-use sample controls and components. The kit contains a component library, several commonly used Power Apps component framework controls, and other utilities that increase developer productivity.
https://docs.microsoft.com/en-us/power-platform/guidance/creator-kit/overview
Before you use the components included with the Creator Kit, use the reference app to learn component behavior and implementation patterns. With the reference app, you'll also learn how to add components to an app.
https://docs.microsoft.com/en-us/power-platform/guidance/creator-kit/creator-kit-explained