It's a pretty logical expansion of the lillial orb, in honesty. It's still laid out the same way, except that instead of each direction being for a particular stat, it's for an element instead. The major difference is that the direction you're going on the orb is determined by the amplifier you have equipped and the points are "spent" automatically. This is pretty clear if you're paying attention to the graphic on the right side of the screen.
However, it's also a unique system and I feel that it's not getting enough credit for that, either. Including from myself early on. The interesting thing about this system is that what determines what you learn is the amount of points in a particular element, and what you equip only determines which elements get points when they're gained and how rapidly. There is a major failure in the interface that is easily noticed if you use the sort option on the screen, which seems to lead some people to believe that the amplifier "has" skills on it, but that is of course not the case at all. If you equip the very first fire amplifier, you can learn every fire skill eventually, it'll just take much longer than with a more advanced one.
I figured that the orbs are activators rather than something along the lines of giving you skills. All the skills and artes and such that a character can learn is already pre-built. It's just a matter of how you want to activate them and when and by using the orbs as activators, you're allowing a certain growth path to proceed. That's what I took it as. Seems like I was right. Though I still haven't figured out what the select button does. Also, combining orbs to create a combination of 3-4 elements are awesome.