Search the library catalogue Access-it for books on Ancient China.
Decide on your search terms.
You could try Ancient China, China - Civilisation, China - History or China - Social life and customs.
Or you could try more specific terms, for example, Great Wall of China, Confucius, Forbidden City or Terracotta Warriors.
Most of the books about Ancient China are in the 931 section of the Non-fiction shelves.
Also check the general books on Ancient Civilisations at 930 using the contents pages and index to guide you to information about China.