How does Newman type letters when sending messages on his mobile phone?

Newman's mobile phone sends a message, that is, he writes Chinese characters in Chinese Pinyin, and then selects the required Chinese characters after homophones appear.

First of all, we should know the "hanyu pinyin" of each Chinese character or phrase. Secondly, each keyboard on the soft keyboard has three letters. Click to display the initial pinyin. Press it twice in a row, and the second letter pinyin appears; Press it three times in a row, and the third letter pinyin will appear.