Is that what the question specifically asks? Or is it 'how do we identify priority issues for Australia's health' which is straight from the 'learn to' column (in this case you would just go through each dash on the learn about column, e.g social justice principles, priority populations groups).
In regards to how the government actually identifies population groups, I would probably just say data from epidemiology data. However, this isn't really an HSC question that would be asked I think