Chapter 4: The Four Tones 四音很重要

Mandarin and Cantonese are tonal languages. Mandarin use 4 tones. Cantonese use 9 tones.
普通話有四音 (廣東話有九音)

wan (1st tone) wān  湾仔 wānzǎi  清水湾 qīngshuǐwān
wan (2nd tone) wán 一起玩  yìqǐwán 好玩 hao3wan2
wan (3rd tone) wǎn  晚安  wǎnān
wan (4th tone) wàn 一万块钱(一萬塊錢)  yíwànkuàiqián

有時候用錯音會笑死人 Sometimes, using the wrong pronunciation and tones can make the Mandarin audience laugh their heads off (see Chapter 8), or puzzle trying to figure out what you are saying. That leads to the somewhat insulting saying of  天不怕,地不怕,最怕广东人讲普通话 (天不怕,地不怕,最怕廣東人講普通話)
There is no easy way to learn the tones other than more contacts and practice with the language.
Using mobile phone APPs, you can practice at your own pace (see Chapter 9).