The cats sharp their claws several times a day and they love to keep it sharp and clean. Outside cats mostly do this on tree trunks and on wooden surfaces. It is advisable to have scratching post for cats kept in the apartment, so that they do not sharp their claws on upholstered furniture. Unfortunately, scratching post is not a guarantee that cats will never sharpen their claws on the furniture.
In our case, both of our cats use scratching post, but one of them occasionally sharpens its claw on the side of the couch as well, from which we try to quit (fortunately, he has not done so much damage yet).
If you find that the kitten has chosen one of your furniture for sharpening its claws, then put the scratching post next to the furniture as a first step. The kitten is a teachable, intelligent little pet. When it goes to the furniture, you should signal your disapproval aloud. Grab the kitty and put it next to the scratching post, and place its forelegs on it. Pet the cat and encourage it. If you have enough patience, you can repeat it several times. If you do not have patient, then you can use a restraining spray on the furniture. Another option is that if you have an orange home, you should place some orange pieces next to the furniture in a small bowl. Cats hate the scent of orange, so it can help keep them away.
The condition and length of the claws of the cats kept in an apartment must be checked regularly. It is not necessary to cut the cats' claws in case if they can properly scuff or care for their claws. Otherwise, or in the case of overgrowth during elder age, we have to do manicuring. It is easiest to do nail cutting when there is a confidential relationship between the kitten and the owner, and the kitten does not get nervous when the owner grab its feet.
If we think we could not do it ourselves (because the cat has come to us recently and has not used to us yet ... etc.), we should turn to a veterinarian.
For nail cutting we should use claw cutting scissors because usual scissors or nail clippers are not the most appropriate tool for it. The claw scissors prevent the claw to get scattered, breaking badly. Each time the cat's footpads must be pressed gently, tilt backwards and let the claws to the come out. About the upper third of the claw should be cut off. It is important not to cut into the pink part because it can cause bleeding and pain. In case of black clawed cats there is no visible elbow pink part, so in this case we should only cut the tip of their claws. On their back legs, the claws are better to scuff, so we almost never have to cut them (or very rarely).