Back cover for the air conditioner.

when the air conditioner is on, the hot air comes from the back. I need a back cover to keep the hot air from blowing out.
I purchased it from Home Depot last night. It was a floor model and the only thing I received with it was the remote. The back cover was not with it. Can I receive one. And I also need an information booklet if you don't mind.
Right now that's my only problem.
Thank you and have a blessed day.