Just send an email to their public diplomacy service or press services if they have one, and ask them if it’s possible to get all three books delivered. They’ll be happy to know you’re interested.
Your embassy will be located in the capital of your country, you have to contact the Chinese embassy obviously, and they speak your local language.
Oof lol. They have another email on this page: http://www.china-embassy.org/eng/sgxx/lxwm/, for media inquiry.
Just to follow up on this. I sent an email to this one as well, and I have not yet received a response.