Preferably, the post should be covered in sisal rope and should be sturdy. If it moves when the cat touches it, chances are the cats not going to use it. Each and every time the cat goes to scratch on the furniture, pick the cat up and bring it to the scratching post. Lift the cat's paws on the post and move them back and forth on the post. Is known to cut down on scratching.
Cats are smart and they learn quickly.
Remember the training period will also allow you and your cat to get to know each other. Your cat will love and respect you much more for it.