To Start, Stop, Reboot, or Terminate the instance
In the EC2 console, click Instances in the AWS left pane. All your Amazon machine instances are displayed, along with their EC2 Instance IDs.
The Instance ID is the default password for the administrator account.
Right-click on the SMA 500v for AWS AMI instance. In the right-click menu, click Instance State and select one of:
Terminate
More information on how to start or stop an instance is available on AWS website: