When you look at the light in distant stars you are really looking back in time explain what this statement means?

Light travels at approximately 186,000 miles per second in a vacuum. If you were this distance away from a light bulb and someone turned it on, you wouldn't see the light turn on until a second elapsed. So, when you see it, you see the state of the light bulb as it actually was 1 second ago. That is, you would see it how it looked 1 second in the past. The same applies for any light source including stars, which are much further away than 1 second away.