I just can't understand the array and how it works in C?

It’s been quite a few days now and I just can’t understand what the array is all about in C.
I watched many videos and even read some articles but all that I was able to understand that array is bits grouped in a parameter that can store multiple values of it’s type, but I still didn’t understand much in how it works in C. Can someone please explain how it works in C and what the array is all about? Please try to explain it as simply as possible.

P.S - I don’t really understand what index 1 or index 0 is about.