If you are new to the Revit Platform API, the following topics are good starting points to help you understand the product. Walkthroughs provide step-by-step instructions for common scenarios, helping you learn about the product or a particular feature. The following walkthroughs will help you get started using the Revit Platform API:
Walkthrough: Hello World - Illustrates how to create an add-in using the Revit Platform API.
Walkthrough: Add Hello World Ribbon Panel - Illustrates how to add a custom ribbon panel.
Walkthrough: Retrieve Selected Elements - Illustrates how to retrieve selected elements.
Walkthrough: Retrieve Filtered Elements - Illustrates how to retrieve elements based on filter criteria.