Spells are cast by meeting or exceeding their DC. To cast Accio for example, the caster must succeed on a Charms check equal to or greater than 20.
Spellcasting- To cast a spell a wizard/witch must first learn it to do so. Wizards at first level begin play with 0 spells known.However, once in Hogwarts or with a teacher/book they can begin to learn new spells. To cast a spell the character must study for 1 hour for every 5 points of the spells base DC and succeed on a DC check equal to the spells DC +5 representing the difficulty in first casting the spell. If they do not meet the required DC they must study again although at only half the time that they originally studied. Upon a successful casting the extra +5 to the DC of the spell is removed as they are considered to have "mastered" the spell. Should the spellcasting check fail by 10 or more the caster has their spell backfire horribly. For example someone attempting to cast a Cheering Charm instead has the subjects attitude towards them worsen.
Saves:
For spells that require a save the save is equal to 10+1/2 the caster level+the appropriate attribute.
The attributes that help determine spell saves are Charisma for Curses and Counter-Curses, Wisdom for Charms and Intelligence for Transfiguration.
Spell Limit- Each character has a set number of spells they are able to learn. They are able to learn up to their spell limit overall from the following schools of magic which are Curses and Counter-Curses, Charms, and Transfiguration. Also, they can have a number of known potions for the Potionmaking skill equal to their Spell Limit.
Templates- Templates are modifications to the spells that changes the way it works. Add the modification number to the spell DC. The caster must then equal or exceed the new DC in order to cast the spell.
At first level the character receives a magical wand. The wand is made of a wood, and core of the player's choice.
Wands are made of a wood, and core of the players choice. A wizard has a -2 for using a wand that's not yours for all spellcasting checks and -10 for using a broken wand. Additionally, upon choosing a wand the wand gains one of the effects listed below. Counter-Curses are either a magical counterspelling attempt or Protego.
Gain a +2 to Charm checks
Gain a +2 to Curses checks
Gain a +2 to Counter-Curses checks
Gain a +2 to Transfiguration checks
Gain a +2 on attack rolls made with the wand
Gain a +2 on Damage rolls made with the wand
Reroll any Charms check once per day
Reroll any Transfiguration check once per day
Reroll any Curses check once per day
Reroll any Counter-Curse check once per day.