Dear Sir, what is you arrival city in China exactly? After you decide, you could check the flight schedule on the website and the international airfare varies from different departure date. For the visa requirements, you could consult the Embassy of China in Nigeria or refer to the page:
https://www.travelchinaguide.com/embassy/visa.htm

Besides, I know in Shunde city, Guangdong Province, there is a Lecong Furniture Market, which is also named as ‘Furniture Trade Center of China’. It is about 40kms away from Guangzhou city, where the Canton Fair is held.