Looking back at the Jobs tab for a moment, we can see examples of three different ways of defining when a job should run:
The first entry, PURGE_LOG, runs according to a defined schedule. DRA_REEVALUATE_OPEN_FAILURES is assigned to a window group that consists of two windows: WEEKNIGHT_WINDOW and WEEKEND_WINDOW. These windows define different parts of the week, within which jobs run at a predetermined frequency.
The third example, RSE$CLEAN_RECOVERABLE_SCRIPT, has its frequency defined as part of the job definition.
The Schedules tab shows information about existing schedules, from DBA/ALL_SCHEDULER_SCHEDULES:
By right-clicking on the Schedules grid, you can build a new schedule, such as this one, which will set up a job to run hourly for the next seven days:
You will find some new terms for specifying the repeat interval in the PL/SQL Packages and Types documentation—such as "minutely" and "secondly." You can also go so far as to specify the exact day and time when a job is to run.