Does anyone know of good tutorials for learning arrays and classes?

So i need to learn how to use arrays and classes but i cant find any good tutorials on them. I am pretty good at coding and learning but i have never needed to use them before. I am trying to learn the basics of them so i can put them all together to make an inventory system. So does anyone know of a good tutorial for just starting with them? Or can someone give me a quick overview? Thanks i am using javascript!