The percentile is to top something % of the course. So say you're 80 percentile, that's top 20% of the course.
HSC Mark is the average of your examination mark and assessment mark.
Not too sure what scaled mark is :/
The raw mark is the raw mark/100 you get in the exam.. which is then aligned to give you the aligned mark. As every subject has different difficulties, a 50 raw mark in say, 4U Maths is different to 50 in 2U Mathematics, so maybe a 50 in 4U aligns to say 80 and 50 in 2U only aligns to 60. But you can check the approximate here,
http://rawmarks.info/wiki/Main_Page