My two sisters married to Australia, and then applied to my parents for the past, which is equivalent to immigration. I am studying now so that I can study in the future.

After your sister has permanent residency, apply for family immigration. As a younger brother, she can't immigrate with your sister. Even they have to queue up to apply for your parents. . If you go to study abroad, it doesn't mean that you immigrate (unless you apply for TR after studying abroad, TR can bring your wife with you) or you can immigrate with skills, and your sister can help you and give you extra points. Then you can come to Australia directly with your wife and children.