Tea
noun
The お just makes the word more polite. Since tea is so important in Japan, it gets the お. Otherwise, you should be able to figure out the meaning as it's the same as the kanji.
おちゃ
The reading is the on'yomi reading, just like you learned with the kanji.
お茶下さい。
Tea, please.
ここには去年、お茶の木が生えていました。
Last year, there was a tea tree here.
イギリス人はよく午後にお茶をのむんですか？
Do British people often drink tea in the afternoon?