"Let's write music."
Translation:E haku mele kāua.
You could translate haku as "create" as in art of any medium. Here's what wehewehe.org says: 1. vt. To compose, invent, put in order, arrange; to braid, as a lei, or plait, as feathers. The problem I have with the answer above is that in Hawaiian, mele refers to the words, not the music.
Here's my answer that got marked wrong: E haku puolo kakou.