Edit each cron field and the tool translates the whole expression into a readable sentence describing exactly when the job will run, so you can confirm the schedule.
Five space-separated fields — minute, hour, day of month, month and day of week — followed by the command to run.
A comma lists multiple values, so 0,30 in the minute field runs at both minute 0 and minute 30 of the hour.
A hyphen defines an inclusive range, e.g. 1-5 in day-of-week runs Monday through Friday.