Since this word is made up of a single kanji, it uses the kun'yomi reading. You haven't learned this reading yet, so here's a mnemonic to help you:
Imagine hearing someone to your left saying, "Hi Da'ri!" (ひだり) which is supposed to be "Hi There," or "Hi Dearie." You turn left and there's no one there. You hear it again, "Hi Da'ri!" Keep turning to the left until you find the person saying hi to you.
What's the name of the mountain on the left?
I will never forget the time that girl got her left ear pierced.