Doing Biz in US, anyone knows?

Hello,
This is my second post trying to get help. if you know please share. Thanks.

I am a Canadian PR and I got my H4 this fall. My family lives in US now. A friend's company in China wants me to be its agent in US/CA. With my legal status in US, is it possible for me to do business in US? What is required? Should I register a company in CA first? Can someone share experience? Does anyone know how to do it? Thank you very much.

Feida