When you start the game, you have no spells ready for use. Once you have rested, you should have all the ones available that you chose when you created your character. This is different from a Mage, who can't use a spell even though he knows it unless it is specifically selected in his spell book. The big advantage of the Mage is that he can learn additional spells from scrolls, which are plentiful. A word of advice - select places to rest VERY carefully.