Maybe I just don't know how. But I enabled the IME in the settings and selected it.

The keyboard is indeed a Chinese one, has the signs "符号" in the left corner but all it inputs is Latin characters. I selected the 中文 (拼音) keyboard.

How do I make it suggest me any Chinese characters?

Besides, the stroke keyboard - 中文 (手写简) doesn't work for me at all. It simply doesn't change the keyboard at all.

I'm using a ported device (OnePlus 3) - maybe I need to install some extra packages?