Ug.

The Magic system and spells are part of the 'depth' of the game that takes time and playing to really understand. The same with making Pretenders and finding the balance between magic (and blessings) and scales (production of units).

Spells and mages can turn the tide of battle quicker than any other aspect of the game.

This is where playing a nation like Ulm is good when you are a newbie so you don't have to worry about all the different spells and effects and can focus more on learning the basics.

The best way to start appreciating some of the magic is playing a race with strong, but not to many different paths/spells to pick from. Good ones are: Ulm (Earth with a little Fire), Man (Nature with some Air), Atlantis (Water with a little Astral).

I'm sorry I can't help you more, but I'm glad that it is far too complex for me to answer effectively since its what makes the game so deep.