Consult Fa-Ju-Shi and Jia-Bo-S

I read your web talk and got many useful informations about visa application. However, I don't have any idea on H1b visa application. Could you kindly give the advice?

I got an offer in US university and I asked to apply for H-1b with premium petition. After long time waiting, I got an message and they asked where to send the approval material. They want me to choose one from Guangzhou,
Bejing, Chengdu or Shenyang. Could you kindly tell that:

1) what would be included in the approval material
2) should all the material be sent to an US embassy in China
3) should I have any approval material
4) what should I take to the Embassy for visa application
5) Can I apply for H1 and H4 at the same time

Thank you very much!