hi,i want to know how i can get infomation on how to visit china.

Visit China for what? This will decide what kind of visa you are going to apply. Some basic requirements:
1. invitation letter. Applicants must submit the original invitation letter from China to book the appointment on every Tuesday or Thursday morning from 10:30 am to 12:00 noon at the Visa Hall. No fax, photocopy or scanned invitation letter will be accepted. The invitation letter should be valid for only 3 months from the date of issue. Alteration or forgery of invitation letters is absolutely forbidden.
2. valid passport with recent passport photos
3. completed visa application form (Form V2011A)
You may be required an interview for getting the visa.

For more info, you can get it from the official web of the Embassy of China in Nigeria: http://ng.china-embassy.org/eng/hzqz/tsyq/