Hello Raeperk. Adding to what arnie said, be sure to purchase the "Usable Couch." It's the one with the description "While still usable, this couch looks like it was abandoned at the curbside by college students who..."

Drag the Usable Couch down from the Decorate Tray and place it in your house. The tutorial should acknowledge it and stop asking you to place it. Please let us know if this resolves the issue for you.