Survival in Alderstone is a difficult challenge, one made manageable through the Skills available to each class. Through use of abilities that must be "actively" utilized and "always-on" passives, each class can mitigate the damage it receives, and increase the damage it puts out.
All Skills require Skill Points to be allocated before they can be used, and Skill Points are earned through Gameplay (one per level up to 60, and then additional skill points can be earned through continued gameplay after level 60 has been reached), or purchased using Gems. Skill points earned or purchased for one class are not available on another class.
At least one Skill Point must be allocated to a Skill (either Abilities or Passives) before they can be used, and all Abilities have 99 Ranks available, whereas most Passives have 10 Ranks available; each rank increases the effectiveness of the Skill in question.
Simply speak with Sir Caleb while in the Town Hub to manage the skills on the class you are currently playing, or bring up the Skills panel (mapped to S on desktop, or in the tray on mobile devices). To manage skills on another class, speak with Grisolm and switch to that class.
Abilities are the "active" skills, coming in the form of attacks, buffs, debuffs, or defensive flavors. Each class has 18 Abilities in total available, although only 10 at a time may be slotted into the Skill Bars. All Abilities must be activated through the Skill Bar in order to be used, with the exception of the Knight's Dual Wield ability. Dual Wield is an active ability, but functions like a Passive in the sense that as soon as at least one Skill Point has been allocated, a Main Hand weapon can be dragged and equipped into the Knight's off-hand slot.
Passives are just that; passive skills that are always active, as soon as at least one Skill Point has been allocated to them. Passives serve largely as always-on buffs, increasing various character stats. They do not need to be activated or slotted to the Skill Bar in order to be used. There are 18 Passives available in KingsRoad, will all three classes having the same bank of Passives available to them.
While all three classes have the same selection of Passives available to them, each Class has its own pool of Skill Points, and the skills selected as a Knight (including Passives) do not affect the Wizard class, and so on.
If you find that you are not satisfied with your currently layout of Skills, simply speak to Sir Caleb and opt to 'Reset Skills,' which will reset all allocated Skill Points for the currently selected class. This allows all Skill Points to be reallocated as you see fit. Please keep in mind that the cost of a skill reset is based on the level of the class in question.