The most critical part of any WebQuest is the Task description. This section simply describes what you want the learner to have accomplished by the time they have finished the lesson. Don't include the intermediate steps that lead to accomplishing the Task. Those will end up in the Process section.
The Task description will be short, but it will represent the results of higher level thinking. It should be written in the second person and in language accessible to your targeted learners. That is, address the learner as you rather than talking about them as "the learners will..."
* Remember, the written description of the end/culminating product must describe clearly the goal of the webquest. Task should require synthesis of multiple sources of information (transformative thinking) and it should be highly creative, going beyond memorization, and engaging. In addition, the task should be realistic, doable, and appropriate to the developmental level and other individual differences (age, social/culture, and individual differences) of students with whom the webquest will be used.