On the day of your marriage, your Commonwealth Marriage Celebrant will perform the legal requirements for marriage in Australia. The bride and groom will also need to arrange for at least two adults, (at least 18 years of age) to be present to witness their marriage.
Your Commonwealth Marriage Celebrant will recite the Monitum, explaining the nature of marriage in Australia. The couple will then exchange legal vows (and rings if so desired), before signing the Marriage Certificate.
Your witnesses will also sign your Marriage Certificate, and your Commonwealth Marriage Celebrant will officially pronounce you as Husband and Wife.
You will leave on the day with your official Commonwealth Marriage Certificate.