[rAWfOX]

read the documentaions..... all is there

9. SCHEDULER

The scheduler is used to trigger scripts at a given time. The layout in
ioFTPD.ini looks like this:

[Scheduler]
###
# Scheduler
#
# Event = <minutes> <hours> <day of month> <day of week> Command
#
# Internal Commands:
#
# &Reset : Resets upload/download counters
# &Service_Update : Reloads devices and Restarts services, if bind ip
# of service has changed
Reset = 0 0 * * &Reset
Service_Update = 10,30,50 * * * &Service_Update

Setting something to run every 15 mins would be as simple as:
0,15,30,45 * * * ..\scripts\every15mins.exe

..and every 15mins between 0 & 12.. would be;
0,15,30,45 0-11 * * ..\scripts\every15mins-hours0-12.exe

Remember time in scheduler is UTC! Not GMT or CET etc.
UTC is GMT without daylight savings.

For example if you are located in CET timezone, in order to trigger an event
at midnight every day use: EveryDay = 0 22 * * ..\scripts\everyday.exe
because the difference is -2 hours, at least when I'm writing this.

Day of month is between 1 and 31.

Day of week is between 0 and 6, 0 being Sunday.