The Database Dashboard card in Database Actions provides the Overview and Monitor tabs where you can find information about the performance of an Autonomous Database instance.

• Use Database Actions to Monitor Activity and Utilization
  Database Actions provides the Database Dashboard card, with Overview and Monitor tabs to provide real-time and historical information about the utilization of an Autonomous Database instance.
• Use Database Actions to Monitor Active Session History Analytics and SQL Statements
  In Database Actions the Performance Hub card provides information about Active Session History (ASH) analytics and current and past monitored SQL statements.