Be audibly pleased even if your cat only comes up and inspects the post. You want the cat to take full possession of the post, so never remove it or obstruct access to it. When she lunges at the toy, her paws will land on the textured surface and she'll just naturally dig in. Then she will discover that the post has great scratching potential. A good place for the post is where kitty sleeps or eats.
Many cats enjoy a good scratch upon waking and before mealtime.
Should your cat show interest in any other surface, the fabric on a sofa or a stereo speaker say, place the post in front of the off-limits item to divert kitty's attention. You can later gradually move the post to a more desired location. She knows when you're happy with her. As time goes by, continue to praise her when she scratches, even after she is sufficiently trained. This further cements her good feelings about her post and reminds her that you are pleased.