This means "section" as in part of an organization. Section of a thing is usually 部分 （ぶぶん） or 一部（いちぶ）. Occasionally it means lesson, as in 'section of a book you have to learn.'
The section chief of the fruit factory says orders to you, the fruit employee.
課 (section or lesson) + 長 (long / boss)
= 課長 (section chief)
section chief - or department manager.
the task at hand
課 (section or lesson) + 題 (topic)
= 課題 (the task at hand)
The subject of today's lesson (in school); the task at hand (at work)