How to use EC2 plugin to scale up the cluster

[praveen]

We've a job and that job used run currently. Created label for this job(created same label in the Jenkins configuration). Whenever I run the job Jenkins able to spin up the new instance and execute job. However if all executors are busy on the running slave ec2 plugin has not creating the new instance if new job came up (the new job simply waiting in the queue).

How it supposed to work? Am I doing something wrong. Can someone please help me.