The Overcast Design-time User permission set is required for all users who will use the Component Builder. Using the Component Builder requires System Administrator permissions because it uses a restricted API to save metadata type records. Click here to learn more about permission sets for Overcast.
Component builder can be accessed in two ways.
The Component Library tab houses the components that will be used to display and interact with your backend system data in Salesforce. The components allow for integration, with no code required. In the Component Library, you can see all of the available components and search for the right component based on its intended purpose. In order to use the components, they must be activated. You can also create your own or customize existing components using the Component Builder.
When opening the component builder in create mode with the Create Component button, you will be prompted to select an existing scenario. Selecting a scenario tells the builder to read and use the metadata from the scenario's apex class. You can view the scenario metadata by opening the Real-time Data Viewer for the scenario and selecting the Get Metadata button (
) in the upper right corner.
When opening the component builder in edit mode with the Customize Component button, you will be prompted to select a component definition. If the Component Builder is opened from a detail page in the Component Library (from selection of the component directly), the select list will only show the component definitions that are related to the selected Component.

You can also access the Component builder to build your own components in any Real-time Scenario. You need to simply navigate to the scenario and select the Create Component button and enter the Component Definition Name and Apex Plugin Class(if any). You can also customize an existing component by selecting the Customize button next to an existing component in the Real-time Scenario.

The Component Builder provides a preview screen to render your component definition changes. This is a live, working screen, so the component will show live data from the external system, and you can interact with the component as a normal user would. This means that write operations are also persisted on the external system.
For the preview pane to display live data, you must configure the preview settings by clicking on the cog next to the Update Preview button.

Preview object is the object type that the component will be displayed on, such as Account or Opportunity.
Preview record is the record to use as sample data.
Preview component type specifies how to display the component, such as a record detail or list of records.
Preview Component Types There are multiple types of components available in the Preview Settings screen.

Widget is the default Preview type and is used for components that should be displayed on a record page.
List viewer is for displaying the data as a list.
Detail viewer is for displaying the data as a details page.
Sales order poster is a complex application that requires multiple SAP sales order scenarios and definitions to operate. It is for advanced sales order application configuration.
Object poster is for a single write request to the backend system. It shows an input form and a submit button for user input. After submitting, the response is displayed to the user.