Rich explains this here. I know you have read it several times so maybe try using the example with your items. Just replace the items in the example with your items and create the proxy item.
After setting it up if your having errors post what you have and someone can help. Getting your hand dirty is a good way to learn and understand how the rules work. The rules posted above are for example and meant to help with ideas. If you need more examples use search and the words anti flapping.