The kanji and the word are exactly the same. That means they share meanings as well. You can add the meaning yard to your memory bank as well, if you'd like.
Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word: You look at your garden. It doesn't meet your expectations so you decide it's time to get a newer (にわ) garden. Tear it all down, folks! Getting a newer garden, here!
I'm gonna level the ground in the yard today.
I grow vegetables in our garden.
I have a beautiful garden but my neighbor’s chickens keep eating my flowers.