This is relatively easy, simply put some linatone on their stomachs to keep them busy, and clip away with regular nail clippers. Just be careful not to cut the red line, this is the blood vessel, and will cause the ferret to bleed as wee as being very painful. Ferrets should also be checked for earmites at the vet, and have their ears cleaned once a month. A ferret earwash and a q-tip or your finger work pretty well. A ferret's cage should be completely cleaned at least once a week, and their litterboxes cleaned at least twice a week.
Litter is very important, never use a clumping litter or a very dusty litter.
The best available litter is compressed wood pellets, found in both pet stores and farm supply stores. You may have to go a little out of your way to find a better litter, but in the long run, both smell wise and health wise, it will pay off. Ferrets should be kept indoors, they cannot tolerate temperatures much above 85 degrees, and can and will die of heatstroke if exposed to higher temperatures for an extended period of time. A ferret life span is 7-10 years, so you must be prepared to take care of the day after day, year after year, for their lifetime. Ferrets grow very attached to their owners, and have actually developed bleeding ulcers, and died when separated from a home they have known all of their lives.