Nani ka wahine. means The woman is pretty.
Ka wahine nani. means The beautiful Woman.
Maybe this helps to understand it.
for additional grammar explanations I go to wikibooks, you can't find everything on there but it is certainly useful
So do adjectives always follow the nouns they modify rather than precede them? I wrote he nani la and it was marked wrong.
Blarg! Hawai'ian is probably the hardest language I have tried to learn on Duo. Just when I think I grasp a concept I get dinged!