Damaging the retina display of MacBook Air & ways to care for the MacBook

Hey there!

I just recently bought a new MacBook Air and have a keyboard cover on when using it just incase any mishaps happen. I normally take out the cover before closing the laptop but I had forgotten this one time and immediately removed it once I remembered after an hour later. I was just wondering if the short period of time did any damage to my screen display?

Also, does touching the Retina display with your finger damages the screen? If so, how do you normally open your laptop?

Also, if anyone could link me to a few tips on how to care for my MacBook Air, that'd be great!

Cheers