A monthly recurrence pattern will cause the scheduled item to run as defined by the selected options.

Fields and Buttons
Day x of every y month(s) - This recurence pattern will cause a scheduled item to run on the numbered day of the specified month.
The x y of every z month(s) - This recurrence pattern provides specialized scheduling. This is useful for running a report every second day of every month or every third Monday of every 2 months for example.
The monthly recurrence pattern offers a specialized way of specifying the exact days to run a scheduled item.