Original: To become effective, the proposals must be put to a referendum of all Australians of voting age, and must receive a "double majority": a majority of all votes, and a majority of votes in a majority of States.
Simplified: To become law, the proposals must be put to a referendum of all Australians of voting age. The changes must get a "double majority": a majority of all votes, and a majority of votes in a majority of States.