I think you have all the ingredients to be a lovely, rider. I anticipate that everyone here is going to ask you what else your trainer says, and if you feel you’re not getting the feedback you want, to seek out someone who may do work with you, like riding without stirrups on a longe line. Your trainer in this video is correctly advising you to keep your horse nice and forward. This is a good first step with a green horse.
In general…yes your arms are out in front of you and too high, but I wouldn’t worry so much about where your arms are. Rather, how can you begin to pick up contact with your horse and learn to follow the movement of his body with yours. How can you keep your elbows close to your sides and quiet while letting your hands follow. A lot of the rest will fall into place once you learn to feel real contact. And it’s hard to coach it over the internet from a single video.
I do like that you seem to intuitively stay soft on your horse, and encourage him into forward movement while he learns to rebalance into a new sport that requires him to use his body in a very different way.
Thank you for trusting us through sharing your video, and I look forward to hearing about your progress.