Hold your cat's paw in one hand and gently squeeze it to extend the nails from their resting retracted position.
Before you start, determine how much of the nail needs to be trimmed. Position the grinder in a way that it encircles the top of the claw, and work from the inside curve of the nail.
Smoothly start grinding the top of the nail - don't apply pressure and grind in short bursts.
Repeat for each nail. Don't forget the dewclaw on the front paws!