You will get a mail from DIAC in about 24 hours detailing all information. But here is the snip from my mail on how to upload docs.
PROVIDING DOCUMENTS
Electronic lodgement of applications provides an effective service for applicants to provide documents to the department. eVisa applicants should attach documents online at: https://www.ecom.immi.gov.au/visas/attachment/start.do?attachType=VISA_APPLICATION&group=travel
Don't forget to check spam. Look for a mail with this subject "AUTOMATIC NOTIFICATION OF APPLICATION FOR MIGRATION TO AUSTRALIA UNDER THE GENERAL SKILLED MIGRATION PROGRAM"