Quarantine must be in government arranged accommodation. Quarantine outside of government arranged accommodation will only be available in very limited circumstances.
You cannot arrange to quarantine at home or another pre-booked accommodation. This is due to the significant health risk that cannot be appropriately managed at other residences or accommodation providers. If the mandatory quarantine requirements are not strictly followed and people mix more easily in the community, there is unacceptable risk of COVID-19 transmission in the community.