New to Mac, Misplaced Quicktime File

[Riverrun]

Hi Folks,
I've just dragged a file from the Quicktime program out of it's place by mistake. It's now residing upon my desktop and I want to sent it back to where it belongs. On a PC...no problem...on the mac, I haven't a clue how to do this.
Can anyone help?

 

[Riverrun]

Forget it folks...just discovered the undo button. Problem solved!

I love ​

 

[Riverrun]

Just one more thing, earlier tonight, while trying to force a program to quit, I pressed the coomand+ option +eject button instead of the esc button and she blackscreened. I'm a bit worried about it. I won't have damaged my Mac, will I?

How can I check?