Regarding business visitor

Hi, I am Abbas and I have business in UK. Now I am planning to open a factory in my home country Pakistan, for this purpose I want to buy some machines from china and I am in contact with one of the factory. I want to visit that factory before buying any machines. I have UK business visa and I am Pakistani nationl. Now I am in Pakistan for holidays and want to apply for china visa from Pakistan. Please help me to apply for china visa. What type of documents do I need to submit?