Remove any cushions or pillows from the couch, and open any fabric zippers or fasteners on the couch body. Remove any fabric that can be removed to expose as much as possible of the couch interior. Inspect the couch top to bottom, looking for screws or other fasteners. Use the drill to unscrew any exposed screws, and remove any couch pieces that are easily removable.
Flip the couch over, and remove the carpentry staples attaching the fabric to the bottom of the couch if no other screws or fasteners are exposed and the next step is unclear. Remove all the staples visible on the bottom of the couch, and pull back the fabric to reveal the underside of the couch.
Rip apart some of the seams using the seam ripper if you will not be reassembling the couch and if all staples have been removed and there is still no clear way to proceed. Pull the fabric away from the base down the sides, and remove the fabric completely if possible.
Disconnect any hardware now visible within the couch to separate the pieces. Use a crowbar to pry apart pieces of wood nailed together. Snap metal attachments with the pliers or the crowbar if not reassembling.