Minute
The minute(s) at which the command will be executed.
(0-59, ranges, or divided, *=all)
Hour
The day(s) of the month on which the command will be executed.
(1-31, ranges, or divided, *=all)
Day of the Month
The day(s) of the month on which the command will be executed.
(1-31, ranges, or divided, *=all)
Month of the Year
The month(s) of the year during which the command will be executed.
(1-12, ranges, or divided, *=all)
Day of the Week
The day(s) of the week on which the command will be executed.
(0-7, 7=Sun or use names, ranges, or divided, *=all)
User
The user executing the command (typically "root")
Command
The full path to the command, plus parameters.
 
Help
'Using "*" for a time entry means "all" or "every", and is the same as a range from first to last.
Ranges may also be used, for example "1-5" in the "Day of Week" field means Monday through Friday.
Time entries may be divided and will be executed when they divide evenly, for example "*/15" in the Minute field means "Every 15 minutes".

For more information see: FreeBSD Handbook - Configuring cron(8) and crontab(5) man page.