Auto-indent in Notepad++

We always write code like this formal:

void main(){
  if(){
    if()
    }

But when I use Notepad++, the display is:

void main(){
if(){
if()
}

How do I use Notepad++ to auto indent?

Thanks to Jonathan, I have set it, but it does not take any effect. The snapshot is below:

I am using Notepad++ version 5.1.3.