The term 'heavy vehicle' includes trucks, B-doubles and road trains, buses, trams, agricultural machinery, livestock transporters, tankers, grain and delivery trucks and other long and possibly slow moving vehicles on Australian roads.
To learn more, Click Here - https://www.mylicence.sa.gov.au/my-heavy-vehicle-licence
To obtain a heavy vehicle licence you first need to possess a current class C (car) driver's licence, and meet the minimum experience for the licence class you're after.
For more information, Click Here - https://www.sa.gov.au/topics/driving-and-transport/heavy-vehicles/getting-a-heavy-vehicle-licence
Take a look at the Training Guide for Competency Based Training (CBT) in LR and MR Heavy Vehicles in South Australia.
Download Here - https://www.sa.gov.au/__data/assets/pdf_file/0007/12967/TRAINEE_GUIDE_LR_MR-2018.pdf
Take a look at the Training Guide for Competency Based Training (CBT) in HR and HC Heavy Vehicles in South Australia.
Download Here - https://www.sa.gov.au/__data/assets/pdf_file/0004/6376/TRAINEE-GUIDE-HR-HC-2018_1.pdf