Open Legend uses Banes and Boons to simulate the various effects you might want to apply to your enemies. There are not pre-built spells, instead it’s better to think in terms of abilities. Rather than your wizard only being able to do cone of cold and fireball, you can instead just say they have ice magic and fire magic: where for ice magic they might inflict the Immobile or Slowed banes, or the Barrier boon; and for fire they might be able to set their enemies ablaze with the Persistent Damage bane and illuminate a room with the Light boon. If you want to be able to do a cone attack, or make a big explosion, or zig-zag a lightning bolt between enemies, then you can check out multi-targeting in the combat chapter; these can be combined with any bane or boon (or damaging attack) in any way which makes sense for your character. You also don’t have “spell slots”, I understand this takes some getting used to but it’s more fitting with how most spellcasters work in fiction (you never see Harry Potter or Gandalf run out of spells) and it means you get to do your cool stuff all the time!
You gain these abilities through the Extraordinary Attributes, which are similar to schools of magic (though they don’t have to be magical abilities, just something most people can’t do) and you level them up in the same way as your other attributes to access more powerful effects, do your smaller effects more reliably and deal more damage. If you want to be a pyromancer, then you can put points into Energy. A Necromancer would use Entropy. An illusionist, Influence. You just need to match the abilities granted by an attribute to what you want your character to be able to do, and you can level up as many or as few of these Extraordinary attributes as you like.