New
い adjective
This is a single kanji with an い on the end, meaning you know it's probably an adjective. What's the adjective form of new? It's new.
あたらしい
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: Your family buys you a new Atari! You're so excited! But wait... what's this? This is no Atari. This is an Atara... a knockoff video game system :(
この本は新しいです。
This book is new.
新しいアパートはきれいだし、広いし、会社からも近いんですよ。
The new apartment is clean, spacious, and close to the company.
ごめんなさい。この白いシャツまだ新しいので、今日は赤ワインじゃなくて白ワインでもいいですか？
I'm sorry, this white shirt is still new, so could we get white wine instead of red wine today?