Position of hands in Salaat

Asalaam o Alaikum brother.

I am curious to know why "saudis" (as seen on TV) in salaat tend to have ther hands on thier chest, whereas many people in the UK and Pakistan etc have their hands on thier waist? I would like to know whether this is an issue of School of thought or misled practices. Which is the correct way to pray salaat?

JazakAllah khair for your time and effort