There are a number of database privileges and properties that need to be set for a user to be able to access and utilize the Scheduler. Once the user has been granted the proper privileges they are ready to use the DBMS_SCHEDULER package.
In order for you to create a new job manager you must grant the SCHEDULER_ADMIN role.
GRANT SCHEDULER_ADMIN TO <username>;
This role provides a lot of power for a regular user, allowing the grantee to run any code. If this happens to be a regular user who will launch its own jobs, then it should be granted the CREATE JOB privilege. This allows the grantee to create jobs, schedules, and programs in its own schema.
GRANT CREATE JOB TO <username>;
If the user will be performing other management tasks besides creating jobs and schedules, then the DBA should grant the MANAGE SCHEDULER privilege. This allows the grantee to create, alter or drop windows, job classes, and windows groups,...