Help with my now ~16 week old kitten?

Ok, let me give you a bit of a backstory.

My kitten was born to an "inside/outside" mother. The original owners let her come and go as she pleased and did everything they could to coax her into having her kittens inside. But, she instead decided to give birth outside. At about 8 weeks old, they found homes for most of the kittens, except for two. My girl and one of her brothers. They still allowed the mother to come and go as she pleased, so this meant her kittens as well.

Well, my Aunt who lives next door to them asked if she could take the mother and remaining kittens and find homes for all three of them rather than allowing them to roam the busy neighborhood and street. They agreed to this and found homes for the brother and mother. My aunt brought the remaining girl to a family party a few days after Thanksgiving and I took her home with me.

The first few nights she was very calm and just wanted to cuddle and chase the dog's tail. I kept her in my bedroom rather than instantly letting her have full run of the apartment. She was surprisingly already litter-trained and was very good at using it. Now she she has full access to the apartment and has gotten a bit uncontrollable.

We have a couch that reclines on both ends and she likes to play inside the couch. Everytime she does this I drag her out and tell her "NO" and give her a toy to bat around instead. But 10 minutes later, shes back inside the couch. Nothing I've done has stopped her from getting under there. Even if the couch isn't reclined, she finds a way in. It wouldn't bother me that shes under there if she didn't stick her paws through the cushions amd claw at your butt/legs/anything else that's in range. That hurts!

She also attacks toes and arms and fingers and anything else she feels the need to attack.

My question is, how do you teach a cat what is ok and what is not? I know how to scold a puppy, but is it different with a cat? Usually I'll just bop her on the nose or top of the head with my finger when she's doing something bad because just saying "No" or "bad kitty" doesn't seem to do anything at all. She just looks at me like "Ha. You think that'll make me stop?" Could the 8 weeks of being an "outdoor" cat have something to do with it?

I've had kittens before, but not since I was 7 or 8. I'm more of a dog person but I miss having a cat in the house as well. So I apologize if you're reading this question saying "This person is retarded. Lol", but everything I look up online is no help at all. I'm just looking for opinions of fellow (more experienced) cat/kitten owners. No thumbs down will be given by me unless the advice given will harm my kitten. (Such as "beat the **** out of it, then it will behave!" Please... I've seen the effects of that when I was a kid. My dad wasn't too patient with a 12 week old kitten.)