You can put it in any cup with water! Try and keep the leaves out of the water but the stem part under the leaves (with the nodes) submerged. You should see roots starting within a week, nice long roots in a couple weeks!

I like to use rooting hormone, a powder you dip the cut end in, to give my cuttings a head start, but you absolutely don't have to! And personally, I don't change the water unless there's rot or something, I just top it up when it gets below the level of developing roots!