"I love singing."
Translation:Puni au i ka hīmeni.
DL will apparently teach ʻana (to change a verb into a noun, like a gerund) later or somewhere else. Then the difference would be clear: "Puni au i ka hīmeni ʻana" (I love singing) as opposed to "Puni au i ka hīmeni" (I Iove the song). But for now, adding ʻana got me marked wrong. Twice, in fact.
Also, using "hīmeni" (instead of "mele") as a noun (as well as a verb) is pretty much standard among native speakers here on Kauaʻi and Niʻihau,
,F you mean au vs. kou or ko'u, this is how this works. "Au" translates to I. "Ko'u" and "kou" translate to myand your respectively. So it's just like in English. "Anuanu au." "I am cold." "Pōkole ko'u makuahine." "My mother is short." Those are just random examples I could think of off the top of my head.