Depends on how you define event. If a trade show is an event, then they may want help coordinating printed items, booth set-up, getting banners or swag for attendees, etc.

If the event is an annual meeting, they probably have the dates in mind and a general idea of timeline, and want you to fill in the blanks, get any necessary printing done, nametags, event logos, etc.

It's relatively easy to become a Certified Event Planner, and there are classes in many metropolitan areas (not sure of the cost, though). Oh, and you have to pass the test.