Answer
Run the documented method in the database to extract the Database Task definition into PL/SQL-code format, then wrap that generated code in an .ins file and add it to your repository — IFS's own documentation on 'Including Database Tasks and Database Task Chains in Code' covers the exact procedure. The Task's Schedule (its recurrence/timing) is explicitly not something that gets exported or delivered this way — the schedule has to be set up manually in each target environment after the task itself has been delivered.