The trigger is running kubectl apply. When you create the Job, it runs. You might be looking for a more fully featured background task system like Airflow or Argo.

If you want to manually control the pod creation, you can achieve it through parallelism.

Documentation says:

The requested parallelism (.spec.parallelism) can be set to any non-negative value. If it is unspecified, it defaults to 1. If it is specified as 0, then the Job is effectively paused until it is increased.

You can set it to 0 while doing the kubectl apply. Configuration looks something like below

apiVersion: batch/v1
kind: Job
metadata:
  name: pi-with-timeout
spec:
  backoffLimit: 5
  parallelism: 0
  activeDeadlineSeconds: 100
  template:
    spec:
      containers:
      - name: pi
        image: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never

You can set it to 1 whenever you decide to run.