This video shows the steps to replace the upper assembly (keyboard, trackpad, battery & case) on a mid-2012 Apple MacBook Pro 15" Retina laptop. Article with more information: http://www.hightechdad.com/?p=15188
NOTE: this is a LONG video but it does try to show all of the steps.
WARNING: doing this repair WILL void your warranty so you do this at your own risk. I'm not responsible for any damage or loss that may happen.
Read more product reviews, How-To's, Fix-it's and other articles at: www.HighTechDad.com