Most everyone said whay I would say. But you need to stay behind her. You keep walking off to her side and are spinning her by using the rope on her rump. If you stay behind her that might help yuou keep even contact. Proper long lines, whip, saddle surcingle or something to hold the reins are all important.
You should hole the reins just as if your are driving a horse.
Also it was hard to distinguish your voice commends. Back and walk almost sounded identical. They were low and long. I liked the back as it sounded like a downward transition but I would make my walk more bright and peppy in my voice. Maybe even walk on so it was an extra sylible.