I really can't help to get my head around this homework I was given

So because of the Corona virus, my university is locked down, and we use e-learning. I study programming. I was given a homework in Java, and it goes like this: "Make a runnable class, in wich you create 10 rectangle type objects (so multiple instance of one object), store their references in a block, and randomly generate the rectangle's sides." I just can't get my head around this. Can anyone help?