Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
You have to remember the ある portion. Imagine yourself going to walk outside. But, as you walk, you walk like a pirate. You have a peg leg, a parrot, and a hook. Lastly, you say "arrrrr" (ある). Go ahead, say it out loud while walking around your room like a pirate. It will help.
I’m planning to walk to school.
It's the first time we've walked holding hands in a long time.
I’m so fat that when I walk down the street and step on a penny, I squeeze a booger out of the Queen’s nose.