I have booked the tickets up to Chita. After Chita, I want to go to Manzhouli (China). Any idea how to do that?
I'm assuming you don't want to drive (that's still an option though) but you have the choice between flying or taking the train. According to Rome2Rio
Both cities have airports and both Indonesian Airlines and Air China have a service between the two, though the airport in Chita is a little far from the center of town.
There's a train that leaves twice a week to China from Chita 2 station which is closer to the city than the airport. There's also a night train which interestingly enough seems to take less time, at least according to the website. It's operated by Russian railways