I will arrive at China Beijing airport T3 at 5:50 am on AIR CHINA CA 174 from Australia and then need to depart from T3 8:35 am same day on Siberian Air S7 864 to Novosibirsk.

How do i collect my check-in Luggage and then check my luggage in and get a bording pass for Siberian air to Novosibirsk without going through customs so that i can remain in transit. (for most airports in the world you have to go through customs to collect your check in Luggage)

Can you give me a step by step guide how to do this withough going through customs?
Thankyou very much.