My custom armor doesn't work

Hello everyone. I have a problem with my custom armor models ALL OF THEM. I don't know why and i've watched 100 tutorials but none of my custom armor models work:(
I created this for example

then i imported it into the mcreator

and made an armor pack 

and like every youtuber says everything's done and will work, but then happens this:(

I've already tried to do this so many times, but mcreator doesn't want me to do custom armor😭