It is three stars in the middle of Orion, surrounded by four stars. Taurus is in the west and north, Canis canis in the east and Gemini in the northeast. The so-called "three stars are shining high" means those three stars.
"Three stars are due south, and the New Year is coming" are the three stars in the middle of Orion. Whenever these three stars are due south, it will be the Spring Festival soon.