CRON accepts 5 fields separated by a space these fields should appear in the order minute hour day-of-month month day-of-week
each of this fields can contain a number, range of numbers or the * wildcard
The numbers can be zero padded so 05 = 5 and
A range can be identified with a dash or comma such as 1,3,5,7-9,12 You can also use */n to say every n for example */5 in the first column means every 5 minutes.
So if you want a scripted input to run every day at 9:05 am you would put. 5 9 * * *
If you want it to run at five past the hour between 8 and 12 and again at 16:05 you could put 5 8-12,16 * * *
Or every 10 minutes but only in March */10 * * 3 *
Search for cron in google for more details and examples.