There are 3 simple steps, but dont be fooled, these involve alot of work.
You can find all the links you need here: http://bcorporation.com.au/become-a-b-corp-1
1. Meet Performance Requirement
2. Meet Legal Requirement
3. Make it Official
If you would like further information, Call B-Corp at 03 8534 8019 or Email them at email@example.com.