How they work
Routines appear inside the "For you" section, when you plan your day.
Routines every month
Just select the "Day in month"
Routines every two weeks
Will be possible soon with a future software update. Until then you can set it as weekly.
Reminders for routines
In a future update you'll be able to set a reminder one time for a routine so you'll be automatically reminded on those days.