how to number sections by chapters

[Ricardo Picininia]

Hi,

I am using Lyx 2 to write my thesis. I am facing a problem with numbering
sections inside the chapters. I want to have
1. chapter one

1.1 section one
1.2 section two


2. chapter two

2.1 chapter one


now it is in the form of

1. Chapter one

1. Section one
2. Section two .
...

could you please help with this.

Thanks

Ric