All puppies can be loony and destructive, what you have to do is reward behaviour you like and divert attention you do not like. If your puppy likes chewing things to destruction then rope pull toys and chews are very good, as are bones. It works. Bones taste nice than furniture you know. The Cocker is an intelligent breed and will soon have you trained to it's satisfaction.
But as it is training you remember that the beast needs things to challenge it, so putting a meal in a treat ball (dry kibbles) is one way to challenge your dog, unfortunately you can get sent into the next country as a high speed left wing player shoots the entire length of the property sending kibbles out like rifle bullets before connecting with you!
We are now three weeks into owning Lord Bertie Lissie, who has come in, turned the world upside down (along with the Labrador) and screams on regardless! He is an eccentric, loveable character with a permanent "What ME?" expression on his face. He has figured out how to get very toy in the room and gather them before handing them back to the other dogs, he also has a way of trying to look the picture of innocence as he is tap dancing on your head when the alarm or Bertie, goes off...