My flight will arrive to Beijing Airport at T2 on 9th of May at 1.15 a.m.

Then I must go to T3 for my next flight at 5.00 a.m. I would like to ask about cross terminal free shuttle bus because as I read shuttle bus is only go from T3 to T2 to T1. Then I would like to know this route it will be cycle from T1 to T2 and then T3. Am I right or it just from T3 to T2 then T1 only ? Thank in advance