Generally speaking, unless you are ranked first internally in the subject, and you also achieve the highest HSC exam mark within your cohort, it is unlikely that your own HSC exam mark will affect your Assessment Mark (i.e. the mark that reflects your internal performance). The moderation process (which applies to all subjects) considers two main elements, being your rank in a subject and the HSC exam marks achieved by your cohort in the subject (including yours). Essentially, the highest Assessment Mark (which would be awarded to the student ranked first internally) is adjusted to equal the highest HSC exam mark of any student in the cohort. The same also applies to the lowest Assessment Mark (which would be awarded to the student ranked last internally), that is, it is adjusted to equal the highest HSC exam mark of any student in the cohort. An example of the former would be if student A were ranked first in a subject, and the highest HSC exam mark achieved in Student A's cohort was 90, Student A would also receive 90 as their Assessment Mark.
For ranks other than first and last, the Assessment Marks will not be equal to their equivalent HSC exam marks, although they will be very similar. Overall, the main goal would be to rank as high as possible by performing favourably in your school-based assessment tasks/exams, which will help you maximise your Assessment Mark. Once you complete the internal component, the goal becomes to perform at the best possible standard in the HSC exam, so that you can maximise your HSC exam mark for that subject.
I hope this helps!