This subject was never covered while I was at the Seminary -- not too surprising, since most seminarians didn't have houses to sell. The professors never mentioned the practice, and no one brought it up as a question either (unfortunately).
So I have this big gap in my knowledge of "how to be a good Catholic" -- though I can make a good guess based on what I DO know.
I know that first of all you need to have a genuine love and devotion to St. Joseph, and not treat him like a magic lamp. On the other hand, a childlike trust in Jesus' father is a good thing, and pleasing to God.
So I suppose I should find a good prayer to say, and perhaps put a St. Joseph statue in my current house and we could pray before it every day.
(Those who promote the statue say you're supposed to dig up the statue and place it in a position of honor in your new home.)
Maybe it's just me, but I don't like putting anyone on the spot -- neither family, nor friends, nor acquaintances, nor saints.
Matthew