To understand how this screen works, please read the Build Broadcast documentation.
To learn about adding buttons with links to text cards please see this article.
Text Cards allow the Team Admin or Global User the ability to share a briefing or simple text on the Team Member's screen. Up to 700 characters may be included and the number will automatically count down as text is added. If more text is required, simply add another Card to the Stack.
How it looks when delivered to the App: