It seems that there is no bus that can go directly from Huangguoshu Waterfall Scenic Spot to Libo Xiaoqikong. However, there are buses from nearby Anshun to Libo; you can also take a train to Duyun in Liupanshui, and then transfer to Libo Xiaoqikong. I suggest you go to the Huangguoshu Waterfall Scenic Spot to find out if there is a direct bus to Libo. for reference.
Huangguoshu Scenic Area is located in Anshun, which is more than 300 kilometers away from Libo. First go back to Anshun City from Huangguoshu Scenic Area. There is a bus from Anshun East Bus Station to Libo (only one bus, departing at 14:00 every afternoon), and then transfer to the bus to Xiaoqikong Scenic Area after arriving at Libo Bus Station.