Well, actually, that is not that hard.
While I have no idea how to read Chinese
I learned and remembered meaning of certain hieroglyphs, so can get general idea about what is written there.

That datasheet contains nothing special, just says offsets for different characters and how they're mapped into rows and columns
forget to say, it also has complete set of pseudographics, so you can draw windows, some shapes, etc, using it.

You can use this list to see what characters are supported:

GB 2312 - Wikipedia