This means they can be used with any arcane school. Regardless of the type or source, the number of Perfect charges a character may bear is equal to their Artifice level. Characters without Artifice may not hold Perfect charges at all.
Artifice allows an occultist to draw Perfect Charges out of magical items or places of power, which is a process known as Channeling. In order to channel from an item, a character must hold it, close their eyes, and then take a slow three count: “Channeling 1, Channeling 2, Channeling 3,” after which they drain the item of a number of charges up to their Artifice level, which is the maximum any character can hold outside those awarded from rituals. If they are drawing Charges from a Place of Power, they gain this full allotment after they meet whatever other requirements the location has. Note that Places of Power are all unique, and these requirements will vary widely based on location, size, stability, age, and myriad other factors. Most places of power will have a physical manifestation of their nature, and it is this manifestation which must be interacted with in order to channel at the location. Typically, a character will only be able to Channel from a Place of Power a limited number of times per day, but each time they do, they get their maximum number of charges.