PS cats can be trained to scratch where you want them to scratch.
Make sure they have enough scratching places, including a cat tree. Cats like to stretech out when they scratch.
Offer several different surfaces for scratching. Sisal, cardboard and carpet, even wood are all things cats might like.
Offer different "shapes". Some cats like to scratch on flat surfaces, some like curved surfaces, some like upright surfaces.
Incorporate the scratching furniture into your interactive Games with your cat. Drag the string up the post so she climbs it and gets the feel of it under her claws. Toss the mouse or crumpled paper up the tree or under the tunnel of the scratcher.
Teach by example. Cats are the original copy cats. When playing with her, periodically go to her scratchers and scratch on them yourself. Make happy noises when doing it.
When you find her scratching something you don't want her to scratch simply pick her up, gently, and bring her to her own furniture and show her what to do. You can hold her paws very gently and move them in scratching motions.
But most importantly you want to make sure there is furniture for HER upstairs that she is allowed to be on and allowed to scratch. It's not fair to not let her scratch the sofa, but not give her anything she CAN scratch. So get a cat tree or cat condo and some sturdy posts up there and teach her to use them.