How to use user scripts feature

[caynebrister]

https://github.com/AUTOMATIC1111/stable-diffusion-webui-feature-showcase#user-scripts
I am trying to use the feature linked above, but the code example doesnt really help with understanding how it works. i am trying to make something that loops through my prompt and changes the cfg aan step setting for the same prompt and seed. I understand the logic I would need for the loop, but I dont know how to set parameter values for user scripts or even how they really work. I wish the docs went into more detail. Is anyone able to explain how it works and how to set the values such as cfg and and step or even the seed within the custom script?