Even without upgrading your version of DP, this is easy. Click the 'Schedule' tab in the backup specification you want to schedule, right-click on a date, and pick Schedule. Click the Daily button, pick your first time, check the starting date, the type (Full or Incremental), and click OK.
Right-click on the date again, select your next time, and pick OK. At the bottom of the schedule screen, below the calendars, you will see this next time set. Continue this process until you are done
By default, Scheduler Granularity is 15 minutes, if you wanted to schedule a backup, say, at 10 minute intervals, you can edit the 'global' file to allow a schedule granularity of 1 minute
If you are on a UNIX-based system, you can also add a line to the 'crontab' to run
/opt/omni/bin/omnib -datalist [name] do not include the [ ] marks
and set the 'crontab' to run tisi command every 30 minutes