Take a Minor Action - Focus.
No skill test is required.
This is optional, but failing to perform it out causes more Complications.
Pay the Resolve cost (which is always at least 1).
Take a Standard Action - Skill Test.
On the skill test, each failed roll results in a Complication. A roll of 20 causes two Complications. If you didn't Focus immediately before casting the spell then a roll of 19 and 20 both cause two Complications.
Tools such as rituals, circles of power, sorcerous garb, talismans, offerings and so on can all modify casting. Human sacrifice can also modify it but your characters are not going to be doing that.
The GM has the option to make a spell casting skill test a Test With Consequences. The player can request this but the GM has the decision. In this case the spell automatically succeeds but the chances for Complications are much, much higher.
A few spells call for secondary skill tests. Failure means that the spell works but is not under the sorcerer's control.
Momentum from the test to cast the spell can of course be spent on the secondary test.
You can counter another caster's spell, turning their skill test into a Struggle. In an Action Scene this requires a Reaction.
Countering requires three things:
You must be able to cast the spell.
You must pay the Resolve cost of casting the spell.
You must witness the casting of the spell.
A character who permanently sacrifices Fortune points suffers their refresh and maximum reducing by 1.
As written, enchantments and curses cannot be broken, but a gamemaster might have narrative reasons for allowing it.
Curses are the stuff of legends. Powerful enough that the threat is scary, rare enough that people wonder if they even exist.
When a character casts the spell, the character gains a single use of a special ranged attack created by the spell. They still need to make the Ranged Weapons attack, and the spell’s effect ends after the attempted attack, even if the attack missed. It is a normal ranged attack in all regards.
When a character casts the spell, it is a Struggle between their Sorcery skill test (base D1) and the target’s Discipline test (base D2). Momentum from winning this Struggle can be used on Enslave Momentum Spends to determine how potent an effect is achieved. Once the spell is successfully cast, it is a free action (no skill test) to give an order to the target, within the limits of the spell’s effect (determined by the Momentum spent)