Some Lords and Heroes are Wizards, and have access to one or more spell lores. Although you won't generate the spells that your Wizards know until you start to play your game (see the Fighting a Warhammer Battle chapter) you do need to make a note in your army roster of which spell lore each of your Wizards will use. If you have a Wizard that is allowed to choose specific spells, you must select which spells they are at the time you pick your army.