For each reminder the [ ] denote option attributes. label is any label you desire. date can be any valid singular date. time can be any valid singular time. X is any positive integer. If no time is specified it is assumed to be the current time.
label every X (days|weeks|months|years) [at time]
Repeating reminder runs every X days, weeks, months, or years at the specifed time
label on date [at time]
Singular reminder for the specifed date and time.
label at time
Singular reminder for the specifed time today.
If the time specifed has already passed, the reminder is scheduled for tomorrow.
label every X (minutes|hours)
Repeating reminder every X minutes or hours for today's date.
label in X (minutes|hours)
Singular reminder for X minutes or hours from now.