I had the above set up in the arena for lessons on Saturday, so out of laziness I schooled it with Kat.
We started with four trot poles set about 5 ft apart and focusing on very square turns to and from the poles, making sure I had a nicely forward trot and allowing the poles to set her back a little bit. I then raised alternate ends of the trot poles so she really had to lift her legs. She was unthrilled the first time and casually leapt over all of them before returning to the trot, so I rode in a very slow trot to the poles the next time and she started to figure it out.
Once I felt like she was totally warm, on my aids, and ahead of my leg (which could be the subject of an entire extra post. This mare has really been struggling with staying in front of my leg), we switched to just jumping the oxer. I again focused on swinging the shoulders around the hindquarters, setting her up well for the effort, and actually releasing. Because... I have serious release issues right now.
After two good efforts at each height I'd dismount and put the rails up. I don't like jumping above 3' often in my arena because the footing is a touch hard, but it's really good for Kat to see big jumps once in a while. The above is the highest we went and the first rail she pulled.
Being a super careful mare, she only had to learn that lesson once.
Kat put in very consistent efforts, and she's learning to use her head and neck better as I'm learning to half-halt with my body so I'm less afraid of her just taking off with me after the fence. I love that we're getting to a point where I can sit in her and add leg and she'll move up, rather than back off when I really sit down on her. Getting there, one day at a time.