Hi I want to know how to ge to Tulou from Xiamen?

Tulou represents a kind of building, not a attraction name. You might need to choose the place you want to go like Yongding Tulou or Nanjing Tulou. You can take high speed train from Xiamen North Railway station to Wuyishan East Railway station, then take direct bus line from there to Wuyishan.

Yongding and Nanjing far from each other?
How to go there ? Can you advise which one not much tourist and How long from Wuyi shan station

Yongding and Nanjing are not far away from each other. The most common way is to hire a car or join group tour to these Tulou. Nanjing might have less tourists than Yongding and the distance is around 550km between Wuyishan and them. It is suggested to visit Tulou first and back to Xiamen, then you can go to Wuyishan.