From what i learnt from my trials, just make "close reference" to the extract as they say so that could be talking how a meaning of a certain extract is emphasised in one poem so e.g the 2020 HSC ts eliot extract, u can talk abt how the feeling of hopelessness conveyed in the last lines is prevalent in Preludes through the use of fragmented voice, setting etc. (just making shit up lol). Similarly you can talk abt how a technique used in the extract is used in another poem to produce an effect or convey a similar meaning and so on. Just as long as the paras clearly tie back to the extract or the question abt the extract, u should be fine.
Id also consider Mod A and Orwell since an extract Q may pop up there, they really threw me off when I first did them since Im used to the normal structure of "How does X,Y in this poem ...." but its not so bad when u know how to adapt it. Pre sure the nesa workbooks for eng have sample essays for those type of qs as well. Ofc this is just my 2 cents lol, hopefully someone whos done the hsc or is good can offer their side too.