One at a time. Reward as soon as a nail is done with lots of praise and treats. You might not get all of them done for a while, but trying to do all paws (or even all toes on one paw) can be overwhelming to a dog who is afraid of nail trims. You may have to start by 'pretending' to do a nail in the beginning (put a bit of pressure on the nail with your finger while holding the trimmer, to simulate a trim).
I've rarely ever had to trim any nails of dogs I've had - they've always managed to wear them down on their own - but I did have a dog who, every once in a blue moon, did need to have nails clipped. She HATED it, and would threaten to bite whenever I tried. So I began introducing her gradually, rewarding when warranted, and - oddly enough, this helped her the most - I let her play with the clippers after we were done. I imagine playing with the clippers could be substituted with playing with a toy (would make more sense, but hey, she was a bit weird
). Her phobia eventually went away.