I'm not sure why it IS confusing... I asked myself the same question when I was looking at it. I think the concept is relatively simple. Can a future Parliament be bound by the MANNER and FORM put in place by a previous Parliament? The answer - according to the Trenthowan case - is YES - if they themsleves follwed the correct manner and form in enacting the changed manner and form process... however, bear in mind the supposed lower heirarchy of the Australian Parliament then the UK Parliament. However, consider also the redefinition of Parliament witht he Parliament Acts and the result in the Jackson case which confirmed that the Parliament Acts were valid on the grounds that,
a) the 1911 Act said when passed by such a procedure they would become ACTS... it wasn't delegated legislation, and
b) they hadn't EXTENDED their powers (the commons) with the 1911/49 Acts, they'd merely reduced the power fo the Lords.
My argument to that would be that by REDUCING thw power fo the Lords - how can the power of the commons NOT have been increased?
But essentially it is a very straightforward concept.
Looking at opast exams from my university I doubt very much you'll get aquestion that relates SOLELY to manner and form - you'll get a question asking you to dioscuss the concept of Palriamentary sovereignty - whereby you will be required to look into the DICEYAN view - where you'd perhaps discuss the manner and form argument, the enrolled act rule, implied repeal, the ECA 1972, Factortame, Thoburn (Metric Martyrs), Jackson etc... I doubt it would be manner and form alone.