Paper 1 requires certain skills. Not only must you understand the text(s), but also you have to express your ideas in a well-structured commentary. Like any skill, commentary writing can be perfected with time and practice. Although the exam is 1.5 hours at SL and 2 hours at HL, there will have been hours of preparation beforehand to refine these skills.
Furthermore, if you are looking for a quick overview on how to approach Paper 1, you may want to check out our page on Paper 1 tips. It also helps to look at previous exams and sample responses, using the assessment criteria for Paper 1.