title: How to schedule a task with airflow
body: <p>Unfortunately even after reading the many questions here and the FAQ page of the airflow website, I still don't understand how airflow schedules tasks. I have a very simple example task here:</p>
  
  <pre><code>from airflow import DAG
  from airflow.operators.bash_operator import BashOperator
  from datetime import datetime, timedelta
  
  default_args = {
      "depends_on_past": False,
      "start_date": datetime(2020, 5, 29),
      "email_on_failure": False,
      "email_on_retry": False,
      "retries": 1,
      "retry_delay": timedelta(minutes=5),
  }
  
  dag = DAG(
      "example_dag_one",
      schedule_interval="30 8 * * *",
      catchup=False,
      default_args=default_args,
  )
  
  with dag:
  
      t1 = BashOperator(task_id="print_hello", bash_command="echo hello", dag=dag)
  
      t1
  
  </code></pre>
  
  <p>My naiv view would be that this task would be run on May 29th 08:30. But as the time passes, airflow has not scheduled that task. If I change the cron expression to something like: '* 8 * * *' It will schedule a task every minute.</p>
  
  <p>When I however use the same DAG with a start date of yesterday (so May 28th in that case) the task will be scheduled at 08:30, yet it's execution date is the 28th (even though it ran on May 29th) and the start date in the web ui is May 29th. This is VERY confusing.</p>
  
  <p>What I want from airflow in the end is simple: "Here is python code, run it on this time day". So how could I achieve that. Again let's say I want to schedule a task on 08:30 every day starting tomorrow.</p>