International Flight Connection at Guangzhou Airport.

Hi ,
my travel agent said I get assigned seat in Baiyun . So, will they be able to assign me a seat for me and my daughter together ? I already have the ticket but no assigned seat from LA , USA -Baiyun, China.
Do I have to go through Immigration and security or just have to go through security or just the Immigration after arriving from USA to Baiyun airport ? Do I have to claim my baggage or not? All the connecting tickets bought together in same ticket and I have connecting flight to Nepal after layover.
And how will I know where I have to go just after on arrival to Baiyun Airport?
Thank you!