The Skill tree works as following. The trunk is what connects you to your three standard skills, Strength, Skill and Magic. From there it connects to two branches for each. There are six branches and out of those six you can only pick three. Ounce you picked your three you move to your final part, the actual skills that you can use. There are five usable skills total in each of them so you should have a total of fifteen but out of the fifteen you can only pick ten, unless you're a human, then you can pick eleven.
The Offensive skills are, One handed, two handed, unarmed, strength, and power attack.
The Defensive skills are, sheild, armor, leadership, observation, and stamina.
The Combat skills are. Archery, speed, projectile, dual weild, and combo.
The Non-combat skills are, crafting, poison herb, survival, traps and agility.
The Arcane skills are, light, dark, illusion, summoning, and mind.
The Magic skills are, healing, holy, buff, charm, and defence.
If you need anymore help with this then pm either Rensaku or Xoia