XiaoBaiTu, Pjing: questions about I-824

Hi,

I hold a green card and am applying for immigration visa for my family in China by the Following-to-Join category.

The National Visa Center sent the approval notice,I-824, to GuangZhou Consulate last week.

The following are my questions.
1. How long will it take to receive Packet 3?
2. Who will mail Packet 3 to me? NVC or the consulate?
3. Packet 3 will be mailed to my family in China or to me in US?

thanks