Nice work. Pinch the top out at the desired height so it will begin to bush, You then keep pinching out those stems as they get long enough. Keep the leaves on the stem at the moment as thes are currently helping the plant grow. You can then take thes off at a later stage (guesswork) when you have more leaf growth on the top. If you get new shoots growing out of you stem it is best to rub them off as they appear rather than have to cut them off - less chance of regrowth. Hope that helps.