Focus on these questions:
1) What are your reasons for choosing this specific course? Why do you want to undertake postgraduate study at this point in your academic or professional career?
2) How are you qualified for the course? This may be about your prior work experience or evidence of research or reading in the subject area.
3) How will the course benefit your future career plans?
What are your goals? What skills do you want to develop? How would this course prepare you for the future you envision for yourself?