What is the relation between arguments used in YAML and class arguments in the yolov5 implementation by ultralytics?

I was working on fish detection and tracking system in 3 dimensions using MS Kinect, and used yolov5s for RGB frames. I wanted to experiment a bit with the architecture

of yolov5, but as a beginner i am struggling to find the relation between the arguments in the classes used in models/common.py file and the arguments used in YAML file in the Ultralytics repo. Can anybody help ?

PS : If you can add in some resources from where i can learn about the architecture and layers, then it would really help. Thank you !