Dry-fire...the secret to success. Cheaper and easier too.
Phase 1. Get a water bottle, take off the lid, fill it full. Then walk around the house holding it with both hands, arms extended. Utilize the walking methods illustrated on the multiple YouTube channels. You spill, you are not stable enough. If you work in an accommodating environment, take the water bottle and set it near your workstation. Everytime you move, use the bottle.
Phase 2. Superglue a WD40 spray tube to the top of the water bottle and do the same thing, but locate targets and start doing transitions as you move around.
Phase 3. Turn off the lights, do this in the backyard, even at the range.
Phase 4. Same bottle as in phase 2, but add in "Pew, Pew" frequently.
Yes, phase 4 is just having some fun. Seriously, 10 minutes a day for a month will teach YOU more about shooting on the move that you can ever learn burning $400 of ammo in a $400 class...for 50 cents max. I tell students to do this before taking a class, and it is obvious those who took it seriously and those who did not. I have been know to toss a water bottle at a student and send them to the parking lot to run around cars so they could focus on this and get it down.
With newer shooters, I move them from the water bottle to a .22 pistol to fine tune the mechanics of keeping the torso, head and pistol centered on the same index (typically verticle) and isolated from the waist up as they move. This is where a quality instructor can help. But most instructors in the wild don't even know why the pistol (and head and torso) should stay verticle, much less do they teach it. It is a good weed-out question for an instructor.