Hotboost

Hi recently purchased blCk Z21 but can’t get Hornby locos except 1 to work.I have separate program track siding. It goes green light does a little shuffle and that’s it. Take to main track and nothing at all. Latest app , latest iPad iOS . Done a firmware update . My newest loco mallard with sound nothing.I understand the older chipset but mine are all newish and even a TVs brand still nothing. I can’t find much on you tube as far as adding locos Cheers