In Everquest there are 5 different types of Magic's. Alteration, Conjuration, Divination, Evocation and Abjuration. Each one of them serves a specific purpose in EQ. If you've played Elder Scrolls before you'll kind of already know the purpose of each of these. Your spells rely heavily on these abilities. If they're not high enough your spells will constantly fizzle.
TIP: Two good places to find spells are the Abysmall Sea and the PoK Library. The PoK Library is the easiest to access since it is located right in the center of PoK.
Alteration: Alteration generally consists of Heals, Roots, Snares, some buffs use Alteration such as Wunshi, SoW, KeI and Beastcrack.
Abjuration: Abjuration consists of Buffs, generally all "big" buffs like Temp and Protection of the Cabbage.
Conjuration: Conjuration is exactly how it sounds. This type of magic is used for Conjuring things. Pets, Items, Bags and DoT's are the most common things used by this type of magic.
Divination: Divination is like the school of magic that is used when the spell doesn't fit in anywhere else. All the "Weird" spells go here. Really the only Divination spell you'll need is Camouflage
Evocation: Evocation is the school of magic for blowing stuff up. All your nuke spells are Evocation spells.
If you're a caster (or can even cast spells), you'll have two additional skills, Channeling and Meditation. Meditation used to increase your mana regen out of combat and In-combat. Now it just increases your In-combat regeneration and how fast you scribe/memorize spells. Channeling decreases the chance of the spell being interrupted when you're hit or you move.
This is a picture of your spellbook and spellbar. Each and every caster gets one of these. In order to scribe a spell left click it in your inventory and click a empty slot in your spell book. In order to memorize a spell left click it in your spell book and left click a empty gem in your spell bar. You're allowed a total of 8 spells memorized, 10 with AA's. You're also allowed to create spell sets, so you can easily switch out spells to buff, dps, kite, tank etc etc.
Where it shows the little book on your spell bar, right click it and select "Save spell set", pick a name for this spell set and save it. Now when ever you want to load that spell set you right click on the same book and select load spell set. Select that spell set that you want to load.