this dot point (and in fact, no dot point in HSC Physics) asks students to ahve actually done the michelson-morley experiment
in fact, i dont think anyone would have done it, since they used expensive equipment and semi-silvered mirrors, etc
this dot point asks you ot (forget the other words) "interpret the results of the Michaelson-Morely Experiment"
so we are interpreting/analysing the results of the expt, discussing implications, what it suggests/doe snot suggest.etc
the method/aim of the expt comes under another dot point, imoO , but you are right, in that you need to know it (and no, the aim WAS NOT SIMPLY to measure differences in the speed of light or prove the existence of the aether, but thats another story)
i'll start you up:
the result was : a null result
now you do some research , read some textbooks (and yes, every major HSC textbook has info on this) and look on the internet to help you find out what this result signifies/means with regards to the speed of light/the aether, etc
then, if you ned help clarifying some points, just come back and ask and we'd be happy to help you out!