You don’t. Besides, the cat has already ruined it.
Kidding aside, get catnip and a scratch box and hope.
Good luck with that! We have given my cat a wide variety of scratch toys and she still uses the leather couch. If you don't believe in declawing, or can't afford it, you can get something on Amazon called claw caps. They are basically silicone caps you glue onto the claw. They come off as the nails grow, so you will need to replace them occasionally, as well as get the claw clipped, so they can perform as intended.
place packing tape(sticky side out) or double sided tape where the cat scratches. Place enough so that when your cat goes to scratch he or she runs in to the tape. After a while the cat will stop using that spot. Maybe buy a scratching post, might help. Good luck (when it comes to cats, you always need luck hahaha)
Here are a bunch of things you can do. Hopefully you have not considered declawing your pet.
Good luck to you and your kitty.