how to get started with pddlstream?

[Tianyi20]

I am recently learning how to use PDDLstream. Firstly, i admit PDDLstream is a excellent work. However, I feel very confusded seeing so many codes after running examples and seeing the tutorials, like i don't know how the sampler ( generator) works, cause i find both internal-embedded generators and also self-defined generators. So, is there any good examples or tutorial to help get started, in which i can quickly get how to use PDDLstream?