Koori bina is a word that means "good morning" in a language spoken by some Indigenous Australian peoples. It's a way of greeting someone in the morning and wishing them a good day ahead.
Imagine waking up early in the morning and going outside to play. You see your friend and you want to say hello and wish them a good day. In some parts of Australia, people might say koori bina instead of just saying hello. It's a special way of saying good morning that shows respect for Indigenous Australian culture and people.
Next time you see someone in the morning, you can try saying koori bina and see how they respond. It's a nice way to show that you care about the traditional languages and customs of the Indigenous peoples of Australia.