All travellers to Australia (except Australian and New Zealand citizens) must have a valid visa before arriving in Australia. At a minimum, you should apply for your visa 6 weeks before you intend on arriving in Australia.
Visa processing may take some time. After submitting your visa application you should receive a confirmation it has been received and is in the queue for processing.
When you buy a ticket for the conference, you will receive an acknowledgement letter to use with your visa application.
Once you’ve registered and received your acknowledgement letter, use the Australian Government’s Visa Finder to determine the right visa for you.