Basic Elements: Earth, Air, Water, Fire, Light, Dark. Dominance cycles go Earth > Fire > Air > Water > Earth; Light and Dark are mutual opposities and dominance depends on the particular spells.
Tier-2 Elements: 13, for example Earth+Fire = Metal. Trying Light+Dark, Air+Earth, or Water+Fire all get you Chaos. Do not mess with Chaos.
Tier-3 Elements: The 8 possibilities for one of Earth/Air, one of Water/Fire, and one of Light/Dark, avoiding any Chaos. Air, Fire, and Light gets you Plasma. Earth, Water, and Dark gets you Murk. Earth, Fire, and Light gets you Gemstone.
Tier-4 Elements: Creation and Uncreation. Basically everyone who gets this far picks Creation because it's way more useful than Uncreation.
There's 23 major Root Classes (in the Adventuring Guild's classification, which is worldwide ever since a Hero created an extensible worldwide teleportation-portal network), but in very broad terms they could be said to boil down to "casting spells using affinity mana, making stuff using affinity materials, and hitting things with arms and armor made out of affinity materials". Not everybody can be an Adventurer because there's only so many dungeons to go around, and competition to enter the Adventurer's Guild is very intense; people widely suspect you get to go to a more fun place when you die if you have more Adventuring experience first and can tackle more serious problems where you get to wherever.
But, like, the basic idea in magic is - basic affinities that people have, more complicated affinities they can acquire, and then that determines what you can do with aspected mana, or forge from aspected mats, or what kind of weapons and armor you can use? But unless you're literally the Summoned Hero, it's not enough to have four Tier-3 affinities, you still have to party up with enough other people to cover lots of different bases in affinity-dominance combats? Is any of this helping?