fedwells

Hi I am new here I have a 2015 GMC Sierra Double Cab. I have already removed the rear seat and carpet but was wondering what I need to do to remove back wall carpet without tearing it up. Having trouble removing the 2 back plastic pillar covers left and right and along the top by the window so I can install dynamat on the back wall and also find a spot for a amp rack. any help with picks would be appreciated.