I made this cat scratch pole from a cardboard tube but have included a tube you can print with an extension for added length.  I used ¼" sisal rope that I adhered with hot glue.

I think the most important part of this project is the rope.  My cat loves the smell of the sisal and was playing with it before I could even get it out of the package.  You could use regular rope, but your cat might not be as enthusiastic with the end product.  My cat knew immediately that this pole was for him.

This attaches to the wall with two screws.  It is probably best to find a stud on at least one of the screws to really secure the pole. My cat likes to attack the pole now in a flying leap and his 10 pounds amplifies a lot when he is in motion.