Parse CRON expressions and understand their schedule
CRON Expression
Common CRON Expressions
CRON Format Reference
Format: minute hour day month dayOfWeek
Special Characters: * (any), , (list), - (range), / (step)
Examples: */15 (every 15), 1,3,5 (at 1,3,5), 1-5 (from 1 to 5)