I start up close to the stanchion, pup in heel position by my left side - me holding him with right hand (I'm right handed) and with the left hand holding a can of cheese - then I reach out and put a dot of cheese big enough that he can see it, on the stanchion. I bring my left hand back and point to the stanchion with the "look" command. When he's starring at the cheese, I release him with the "away" command. And praise, alot, while he's eating the cheese.
I do this a few times, then I just point with left hand, say "look" and if his head drops to stare at the stanchion - I praise. This is my first step, that my dog can focus on the stanchion when I say "look" -
Then, I release him with the "away" command, and if he goes to the stanchion, I reward with the cheese. I stay up close (within 10-12 feet) till he's got it, that the cheese comes to him but that is where he has to go to receive it.
I've taught three dogs this way and their go outs are great, and we work them everywhere - to a tree - to a car bumper - to just go until you find something that might be a stanchion!
HOWEVER....
The trendy way to teach this with my buddies, is to teach the dog to go out to the stanchion and smack it with their paw.
Personally, I just don't get it, my Bobby is terrified of ring gating that moves (fell over on him once, he's traumatized for life) but many really like teaching the paw touch...
My dogs quickly faded from the cheese ON the gate to the cheese coming to them when they sit at the stanchion...