Three things about sorry business are widely and publicly stated, and an outsider in Australia will encounter all of them.
The first is the restriction on names and images. In many communities the name of a person who has died is not spoken, and photographs, recordings and film of them are not shown, for a period after the death that varies by community and by circumstance. This is why Australian television programmes, museums, archives and books carry a warning that they may contain images or voices of people who have died, and why the warning is addressed specifically to Aboriginal and Torres Strait Islander audiences. Where a name is shared with a living person, that person may be called by a substitute term for the same period. The practice is a protection for the living as much as a respect to the dead.
The second is the reach of the obligation. Aboriginal kinship classifies relationships far more widely than the terms brother, aunt or cousin do in English, so a death draws obligations on many more people than an outsider would predict, and those obligations are not optional. Attending can mean travelling a very long way and staying for an extended period.
The third follows from the second. Employers, schools, courts and health services in Australia are asked to recognise sorry business leave as a cultural and legal obligation rather than as ordinary compassionate leave, and a good deal of published guidance exists on how organisations should do so. That guidance is the part of this subject that is meant to be read by outsiders.