Every one has a diff way to train, the old fashion, archaic way is fine as long as you have a trainer to show you how to use those TOOLS correctly, how the chain is affixed to the dog, how to position it on the neck and show you how much or how little to pop them.
The new more humane way is Pos reinforcement. For most ppl it is an easier way to do it, you don't need precise detailed instructions on how to do it. A gentle leader or Halti (I like the gentle leader better), is a better way but it is still only a tool. You need to teach them to walk, which it sounds like Happy face has tried to help you in that respect.
I can't tell what age this dog is from what info they have given.
A Martingale (nylon w/chain portion) is only good to use if a check chain has been used to teach the dog, the check is only to use the sound, not choke, when they get better with the check chain the martingale is used to periodically "check" the dog when acting up. It will make the sound the dog is use to. This is the way I have been told it works. Putting a choke chain of any kind into the hands of someone who doesn't know how to use it is a bad ideal. You could do more harm than good.