ArcheAge's skill and class system is still something of a mystery to most folks in the West, due to both the language barrier and the fact that XL Games hasn't outlined all the particulars in detail. The company has updated its English-language website, though, and the ability-combination page gives a bit more insight into what players can expect when building characters in the upcoming sandpark title.
The page features a charted list of abilities that, when combined in groups of three, result in a particular class name being displayed. We're assuming that the resulting class will then get to select specific skills from each ability tree. For example, selecting the artistry, calling, and wild abilities results in a class called a Plainsrunner, and reading between the lines on each ability description indicates a Ranger-like class with a pet, stealth, support buffs, and ranged attacks.
If you're looking for a traditional fantasy class, XL provides premade Warrior, Priest, and Wizard templates just above the chart (as well as something called a Chaser), and you can also view brief videos of 10 of the listed abilities via the link in the left margin.