When you train in any skill, you must select one Path. This choice is permanent.
Thereafter, you gain the abilities listed for that Path, as well as any listed under General for that skill.
As soon as you have the requisite amount of Skill Points invested in a skill, you gain all abilities listed for your Path. The requisite amount is 5 for rank 1, 10 for rank 2, etc.
You may spend Feats to gain access to other Paths. For example:
You have 10 ranks of Fire, granting access to ranks 0-2 in "General". You chose the path Firestarter, gaining ranks 0-2 of that path.
You spend 1 feat to gain rank 1 access to an alternate path: "Flameborn".
You spend 1 more feat to gain rank 2 access to Flameborn.
At this point, you cannot spend feats to gain rank 3 access to Flameborn, because you do not yet have rank 3 access to the Fire skill itself.
Whenever you suffer Wound Points, you may immediately cash them in for Injuries of the appropriate type.
The purpose of this is to trade the unpleasant effects of Wounds (i.e. disablement, death) for less-debilitating but longer-term effects (e.g. broken leg, missing hand, etc).
Simply select an Injury of your choice, as long as its description makes sense (i.e. third-degree burns don't make sense when stabbed by a rapier). You immediately gain the Injury, and lose the corresponding amount of Wound Points listed in that injury.
You may select an Injury that removes more Wound Points than you currently have. This does not give you "positive Wound Points", it simply resets them to 0.
Even if your WP are reduced to 0, you suffer from Bleeding Out and must stabilize as normal.
The ability to select Injuries is typically allowed only to PCs and important NPCs, not ordinary monsters.
Armor
As Damage Threshold no longer exists, DR values for Armor will increase.
Armor is now able to add bonuses to Block, stacking with those from shields.
Block, Dodge, and Parry
Block is now an attribute derived from the Fortitude skill and equipment-based bonuses. It is no longer a Skill that can be rolled directly.
Instead, Block is now calculated as (Fortitude modifier, including SP and Con bonus) + (equipment bonuses) + (circumstance bonuses).
When you use the Block reaction, you apply your Block modifier as DR against an incoming attack in your forward arc (requiring awareness). You must expend 1 Stamina.
You may expend more than 1 Stamina, gaining +100% Block Rating to that specific attack for each extra point. This requires no feats or training.
If you reserve a hand for blocking, you gain +10 to Block Rating, and the first Stamina point cost is removed.
Dodge is now a use of the Agility skill. It is used in the same manner as before, but it is no longer its own skill.
Parry is now a use of the Melee skill. It is used in the same manner as before, but it is no longer its own skill.