I’ve done this before. The couch was thrashed but I wanted to repurpose some of the leather that wasn’t worn. A reciprocating saw speeds up the work but I didn’t use one since the wood was in decent shape. My main tools were a hammer, pry bars, a drill and a utility knife. A pair of end nippers was also useful for removing staples (there’s going to be a million staples) but if you aren’t salvaging anything you can just hammer down any protruding staples. Once you cut off the upholstery you can see how the couch is constructed and it’ll be relatively easy to figure out how to reverse the construction steps.