As I have said in the last article just play the game and enjoy it your first play through. Then worry about endgame.
You have 5 skills slot and an ultimate. Use your skill points to unlock first skill of each class skill line and weapon skill line. Choose one skill from each class line, you will get 1 skill points and 1 Attribute point each time you level up and extra attribute and stat point every 5 levels.
In addition to gaining skill points for advancing in character level and you can get skill points when you completion of the main quest in each normal difficulty group dungeon. There are some public dungeons, some special boss of there dungeons will award skill points to you too but you need to at least 2 people. You also will get skill points from Prophet, so don’t neglect the prophet. You will get some skill points from a few misclennaeous quests . There are about 366 available skill points.
You have 5 skill slots and an ultimate. Slot one skill from each class line and two weapon skills. Slot one skill from each class line and two weapon skills use your skill points to unlock them but please remember to unlock healing skill as soon as possible. There are many things that can not be explained in simple language and if you have any problems I will be glad to help you.