Cats nails are relatively simple to cut...assuming you can find the cat
Basically you extend the claw, should be simple and minimal pressure required (basically don't hurt the kitty). If you know how to get the claws to extend then you're pretty much halfway there. If not, play with the kitties, get them used to you doing that, and you'll pretty much figure it out quickly.
Once you get the claw to extend, look at it from the side, you should see a thin pinkish/redish line going through it. This is the "quick", somewhere towards the pointy end of the claw the quick will disappear. Any claw beyond this, is safe to cut. If you are relatively consistent with trimming the claws, the quick will actually shorten some.
It's somewhat purrsonel preference as to which cutters you use, I like human nail clippers. Revlon Heavy Duty Toenail Nippers
. This is what I prefer to use, I can place the blade preciesly and it cuts clean and quickly.