Auto Scaling group - Scaling UP
Firstly, you need create an alarm.
Whenever the Maximum of CPU Utilization is greater than or equal to 75% for at least 1 consecutive period of 5 minutes, Scale UP.
Set all fields as shown below and click on Create Alarm.
After that, you have to set the action on the policy.
When the alarm goes off, add 2 instances and then wait 300 seconds before allowing another scaling activity.
Set all fields as shown below and click on Save.
After created, the policy will be listed on Policies section.