At character generation, your character will have some primary skills and secondary skills, based on Race and Class.
You take your characters Intelligence (INT) + Wisdom (WIS) and multiply by 10 to denote your skill points.
You use these to purchase skills. the maximum you are allowed to put into any skill is 40 points.
Your race and class will give you a bonus start and other things like combat base will allow a level 1 character to have a skill higher than 40 at the start of the game.