Psychic Phase

-------------------------The Psychic Phase-------------------------
Psykers are units that can channel the powers of the warp. They're bullshit. use em!
On the unit page of a Psychic unit it will somewhere say "psychic x" where x is a number. this number is their ability to cast psychic spells and ranges from 1-4 (though only a very few units have 4). The model can get one psychic power per physic ability level. So a space marine librarian With Psychic 1 can take one ability and Special model with Psychic 4 can take four abilities
------Different Schools of Psychic Ability------
Biomancy
Telekinesis
Pyromancy
Divination
Telepathy
Demonology- has two sub categories, sanctic and malefic (if cast by an army other than grey nights or demons will cause "perils of the warp" on any same two dice, not just double 6's)
Different armies are allowed to take "spells" from different schools of Psychic Ability. Check you're codex for
yours'
------Types of Spells------
Blessing - Targets a friendly unit, generally to give a buff.
Malediction - debuff applied against an enemy or enemy unit. 
Conjuration - Summoning demons (usually). summoned models enter with deep strike rules.If summoned unit includes a psyker, roll for their power as soon as they are safely on the board. 
Note - You can not take upgrade for summoned units except for "musician", "Flag bearer" and "champion".
Witch Fire - Essentially mind bullets. these spells function like a gun would in the shooting phase but they work in the psychic phase. after a successful cast, and the enemy fails to "deny the witch" the player must then roll to hit using the ballistic skill of the psyker.
Beam - The player selects a point anywhere within range of the attack. Upon successful casting a line is drawn from the psyker to the point, and any model that the beam intersects with take a hit from the beam.
Nova - AOE blast attack, like a mortor but magic
------Using spells in a transport vehicle------
Psykers can not use Blessings or Maledictions while in a transport vessel. Witch fire can be used if the
vehicle has "firepoints" and Conjuration can be used as normal. 
note: No spells can be cast on units inside of a transport vehicle, only on the vehicle its' self
------Selecting Your Abilities------
Before the game, during the psychic ability selection phase, pick one table to roll on per ability point, per
unit. so for example if a player has a librarian with one ability point they would pick a table. In this example
we will choose biomancy. The player than rolls one d6 to determine which power from this ability school there
character will receive. So if the player rolled a 1 on the biomancy table they would receive the ability "Iron
Arm". If a player does not like the ability they role, they can swap it out before the game for the "standard"
ability of the discipline, in the case of our example the standard ability would be smite.
Psychic focus- If a unit takes all its powers from the same discipline, then they also receive the standard power of that discipline
Force- If the model has a force weapon they automatically get the force psychic power in addition to their chosen powers 
------The Psychic Phase------
Brace yourself, this one gets confusing 
At the start of a players Psychic phase they roll one dice. The result is how many warp charges the player gets for that turn. The player then adds warp charges to their warp charge pool equal to the total psychic level of all the psychers the player currently has on the table. So two Space marine librarians each with psychic level one would add an additional two charges to the players warp charge pool.
To best explain the Rest of the phase we will need an example. So lets say a player rolls a 4 on the dice and has a librarian with psychic level 2. This would mean that the player get an additional two charges (one per psychic level of the librarian) for a total of 6 charges to use in their turn.
the player then selects a pychic ability to use, in this case we'll say iron arm. the player must now roll to "manifest" the ability. The ability iron arm takes 1 successful charge to manifest, so the player decides how many charges he wishes to use to attempt to manifest the ability and gets one dice per charge they decide to use. To manifest an ability, the player must role a 4+ on at least as many dice as the ability requires charges. so for our iron arm ability we need at least 1 successful charge. the player decides use 4 of his 6 available warp charges and thus gets 4 dice. the player rolls and gets the result 6,4,3,1. This means the player has enough successful charges to deploy the ability, however, the opponent now has the ability to "deny the witch" The opponent also gets dice during your psychic phase equal to the amount you rolled on your initial warp charge generation roll (in our example 4) plus one dice per level of every psycher that they the opponent has on the table. for the sake of our example we will say that the opponent has no psychers. this means they have 4 dice to roll during the players psychic phase. so lets get back to our example. the player has just used 4 warp charges in an attempt to use the ability iron arm, which require one successful charge, and passed with two of the dice. The opponent however doesn't want to allow us to get this ability so they use all four of the dice they have been given to try to deny the witch. the check for deny the witch is a 6+ and the player has two successful charges despite only needing one. This means that the opponent must pass the 6+ check on at least two of the four dice that he/she is rolling.The opponent rolls the dice and gets a 6,2,5,1. The opponent manged to cancel one of the players two successful charges however,one is not nullified and so the power is successful In addition the player only used 4 charges and had 6 leaving them with two left, so the player can attempt another ability that requires 2 or less charges to manifest in this same turn. Not only that but the opponent has used the four dice they were allotted for this turn so they can no longer attempt to deny the witch until the next turn when they are afforded more. If at any point the casting player rolls 2 6's then the character suffers "perils of the warp". the player will then roll on the perils of the warp table to see what happens to the unit.
Extra info: 
Having more successful charges then are needed has no impact on the performance of an ability with the exception of witch fire. For witch fire, if the player has more successful charges then they need to cast, it becomes "focused Withcfire" which allows the player to select which model in the unit the spell will hit. The opposing player must deny ALL of the successful charges. If an ability needs 3 charges to cast, and the player succeeds on 3 rolls. the opponent must deny all 3, not just enough to bring the player under the required number. To elaborate the required number for an ability to manifest has nothing to do with "denying the with", it is just the number of successful rolls the casting player needs. to "deny the witch" the opponent must nullify ALL successful rolls made by the player. 
If the spell being used is an aggressive spell, meaning it is being directed at an enemy unit, and the unit it is directed at has a psyker in it, then it is a 5+ for denying the witch not a 6+.Additionally if the psyker in the targeted unit has a higher psychic mastery level than the psyker casting the spell then the roll needed to deny the witch is only a 4+. additionally if the targeted psyker has the "adamantium will" ability, then the roll needed to deny the witch is reduced by an additional one, meaning a higher level psyker with "adamantium will" would need only a 3+ to deny the witch.
------Perils of the Warp------
Roll  /  Effect
1  /  Dragged into the Warp: Psyker takes a leadership test, if passed suffers 1 wound or glancing hit with no saves.If failed he is removed as a casualty and his unit takes d6 S6 AP1 hits (the number rolled by the d6 represents the number of hits the unit takes). The hits come from the psyker for allocation.
2  /  Mental Purge: Psyker suffers 1 wound/glancing hit no saves. randomly select one power from the psyker. It is lost for the rest of the game.
 3  /  Power Drain: Psyker suffers 1 wound/glancing hit no saves. If this takes place during the psychic phase both players loose d3 warp charges (for the play whose turn it is not, this means they loose that number of dice with which to deny the witch)
4  /  Psychic Backlash: Psyker suffers 1 wound/glancing hit no saves.
5  /  Empiric Feedback: Psyker takes a leadership test. if failed Psyker suffers 1 wound/glancing hit no saves. If passed no effect.
6  /  Warp Surge Psyker takes a leadership test. if failed Psyker suffers 1 wound/glancing hit no saves. If passed psyker gains a 3+ invulnerability save, fleshbane, armor bane, and smash until the next friendly psychic phase.