it has two questions . the first writing question is called the integrated writing question. it has a reading part and a listening part. then the question asks you to explain how the listening responds to the reading basically.
in the second question, there is just a written topic. and you are given 30 minutes to write an essay of 300 words or more.
for the second writing question in toefl (the opinion question), use these excelent resources to prepare:
the answer format and tips for toefl writing question 1: