Below, the options are listed which limit when an alarm will sound.
Only between ... and ...
The alarm will only sound between or on the specified dates and times.
Only on ...
The alarm will only sound on the specified weekdays. Note that this option only makes sense when you use a period length of one day. So if you want a periodical alarm to sound on each monday and thursday, the period length should be set to one day. This makes sure the program will check every day if the alarm should sound.
The advanced option will limit the alarm sounding dates and times to any exotic rule you might think of. Click here for more information.
Note that the program works faster if you set the period length as long as possible. For example: If you're setting an alarm to go off every Thursday, set the 'include' date to a date on a Thursday and the period length to 7 days. Setting the period length to 1 day and checking the option 'only on Thursday' will be a bit slower. (This will not be noticeable in 'normal' use of the program.)