For example, you want to type 对不起【duìbùqǐ=sorry, excuse me】:
对不起【duìbùqǐ=sorry, excuse me】is consist of three characters i.e. 对 【duì】,不【bù】,and 起【qǐ】.
1. Type the first character 对 【duì】:
a. Type its Chinese Pinyin (without tone marker): dui then it shows: 对
b. Press spacebar twice.
Note:
After finish typing a Mandarin Chinese character, don’t forget to press spacebar twice. If you press spacebar once, the previous character could be changed after you finish typing the next one.

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2.Now, continue typing the second character: 不【bù】.
a. Type its Chinese Pinyin (without tone marker) bu, for example, it shows 簿, not 不.
b. If it doesn’t automatically show the character you want to type, press <- (left arrow) button, it shows other Chinese characters with Chinese Pinyin ‘bu’ options (see the screenshot).
c. Press down arrow button once or several times until it shows the character you are looking for.
d. Press spacebar twice and the result is 不.

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3. Typing the third word: 起【qǐ=rise, remove】.
a. Type its Chinese Pinyin (without tone marker) qi, for example, it shows 其, not 起.
b. If it doesn’t automatically show the character you want to type, press <- (left arrow) button, it shows other Mandarin Chinese characters with Chinese Pinyin ‘qi’ options (see the screenshot).
c. Press down arrow button once or several times until it shows the word you are looking for.
d. Press spacebar twice and the result is 起.