Layovers in China, Traveling to Thailand

I am traveling to Bangkok, Thailand and have 2 layovers in China: 2 hours in Qingdao and 3 hours in Xiamen.

On my way back to the United States, I'll have 1 layover in China: 5 hours in Xiamen.

I've read reviews that once you get off the plane, it's an ordeal to get your connecting boarding pass. Some travelers have commented that you need to get a temporary entry visa, go through customs, and a whole process to go through. I'm trying to get a clear picture of what I need to do in order not to have any issues.