These names have been provided by the model to indicate a trading entity as understood generally in the Australian business environment.
It is not the role of the model to define these entities. They are defined by the bodies assigned legal responsibility for regulating them and can best be understood by research into these bodies. Many today have website access providing the public with clear definition. These bodies include the ATO, ASIC, APRA, IPA, other federal and state agencies, etc.
Advice on the best entity to be setting up
Key advisors to business who understand these entities are lawyers and accountants and proper understanding of their place in the life of an Australian business operator can probably best be obtained from them.