I don't know about the other post, but here is how I do it. It's also posted on my website below:
1. First find 2 treats that your dog likes. Then take the treats and your dog over to a place on the floor or to a low table like a coffee table.
2.Put one treat in your pocket and set the other on the floor or table right in front of your dog's nose.
3. As you set this treat down, you'll notice that your dog is staring at it and drooling. As you set it down, say, "Leeeave It" very slowly and firmly, but in a normal voice. Keep your hand right there. If your dog leans in to get it, just cover it with your hand and repeat, "Leave It."
4. Wait just a few seconds, then grab the treat and praise your dog wildly telling him what a good dog he is. Then, give him the second treat you have brought as a reward. Don't give him the food he is learning on.
5. Repeat this game several times a day, just for a few minutes. As your dog starts to understand what "Leave It" means, you may begin to move your hand away just a little bit farther each time.
6. Eventually, you should be able to leave a treat on the table, sit in your chair, and be able to trust that your dog will leave it alone, at least for a minute or two.