Michelson-Morley Experiment

Hi Everyone, i have this assignment due in 2 weeks its on recreating a Model in class of the Michelson-Morley experiment to detect the aether. My first problem after a lot of research on youtube clips and just general study is, why?

I understand that they were trying to prove that light needs a medium to travel therefore they were trying to discovder the actual medium it does.

I did go to my teacher and asked her and she said a way to Model the experiement would be to hang a pendulum off a string have a fan blowing against it and release the pendulum each time, however im struggling to see what relevance that has with the experiment.

So Could someone please tell me in lamens terms or with a good analogy what the MMX was actually trying to prove how it was conduct.

- I have read the textbook and i just cant grasp it i have never had this before its really fustrating. Please help thankyou, ask for any added information and i wil be glad to help.