All you have to do is find the predictor and tell him you want to. Just predicting what kind of things. He will help you arrange the dishes in a Taoist way, and then he will tell you how to do it. Generally speaking, Taoist magic needs to be prepared, just what you want to ask, and nothing else is needed. Ask questions and prepare three questions. Only three. Too many words, he can't hold a hexagram. That's all. Prepare up to three questions for the forecaster.
This is the magic of Taoism. He can predict ghosts and gods, which other predictions can't do, so he doesn't have to provide any information. Just prepare the questions you need to ask.