The PoW styles need at the very least a stance from the relevant discipline. Meaning a dip into a PoW class (relevant, a list of Int-using PoW classes and archetypes: Warder, Harbinger, Vigilante Stalker, and the Hidden Blade rogue archetype) or two feats into the Martial Training chain. In addition, some require you to expend maneuvers of a certain type to accomplish their effects. I'm currently building a character that is using Cursed Razor style; the first feat adds on a respectable amount of bleed damage vs cursed targets, the second lets him curse EVERYTHING (when combined with another stance, which also adds extra damage per damage die), and the third gives you a free attacks vs an adjacent cursed creature once per turn.