Welcome snap. Any hearing aid dispenser will commonly deal with newbies who need some extra help. Hearing aids are not plug ‘n’ play. As long as you don’t go in and pound the table and be obnoxious, I’d expect them to be understanding and help get you up and running. And if they’re not, I would say that reflects more on them than you.
It is possible you’re doing something wrong, but this sounds like it could be very well be a hardware/battery issue. You should take the aids and batteries back to see them and just say, Hey, this may be me, but I’m having trouble getting this to work.
I’ve had packs of batteries that had a high failure rate when new.
Or it could be a defect in one hearing aid. Any electronic device can act up when new. A certain percentage are defective and usually this comes to light in the first six months if not at the get-go, where you are.
You have one known good battery and one that isn’t working. Try swapping the two batteries between the aids. If the bad battery doesn’t work in the aid that was working okay, I’d suspect your pack of batteries has a high rate of duds. If the good battery doesn’t work either in the aid that wasn’t working, I’d suspect that hearing aid is defective.