You can start applying when you receive the eCoE from ANU via ANU email. You may receive it approximately a couple of months before the departure (e.g., around November for 2024 February travel students). You can confirm with the ANU Website "International student visa requirements" or contact Bell School (email@example.com) for any further inquiries about the ANU eCoE.
*Remind that both ANU and RU are not responsible for answering any inquiries (including the length of time to obtain a visa) about the visa application processes that the Australian Government authorizes. Refer to the Department of Home Affairs, Australian Government.