Being new to the sport, and the equipment, I am doing a pile of reading and researching to figure out how things work in our guns and why they are the way they are.
I am currently looking at hop ups, and I found this nice little vid on YouTube describing how they work and what they do, how to adjust them and what those adjustments do. It's not too long, and looks to cover everything you would want to know
Airsoft AEG Guns, What Is Hop Up? - YouTube