1. do a carpentry course —> https://www.tafensw.edu.au/howex/servlet/Course?Command=GetCourse&CourseNo=4429
The best practical way to learn about construction. This is a 3 years Apprenticeship. But you don’t have to have an apprenticeship to get into the course

2. Building and Construction (Building) —> http://www.sit.nsw.edu.au/courses/search.php?cid=26959&area=ultimo&Media_Index_ID=47
The best way to know about domestic construction. But getting into this course is very hard. They require industry experience. But still can get in if you can convince the interviewer. This is a one year course. This course allow you to be a site supervisor

Note: You can do both as the same time.