Making an attack roll is when you roll a D20 and add your attack bonus. This will be your attack roll value. You use
Your hit roll is the attack roll you use to compare vs the dodge value.
Against defence,a hit roll is compared vs the defence value. If the hit roll value is equal or higher than the defence value. An attack is considered to have hit. If it is less, an attack is considered to have missed
If the hit roll value is 10 or higher than the defence value. The hit would have considered to have critically hit.
The formula for defence is
10 + (dex mod + 2, capped to armor dex cap) + armor defence + defence proficiency
Armor comes into play when an attack hits a target. You reduce the damage done by the following value:
Damage reduction = Armor - Armor Piercing Value.
Armor works against all attacks that require a attack roll.
Armor is counted as 1 Armor reduces 1 damage from every 10 damage done. So 8 damage with 8 armor means 0 damage done.
Armor Piercing can come from weapons, feats, martial masteries, spells as well as many other sources, Armor piercing reduce the armor value
Saving throw comes against certain effects. There are three types, Reflex, Fortitude and Will. All 3 follow the same mechanics.
Your saving throw roll is equal to:
D20 + Saving Throw modifier
Basic saving throw refers to saving throee with a set success or failure. You compare the saving throw roll vs the DC. If it is equal or higher than the DC, you are considered to have succeeded, if you rolled lower than the DC, you are considered to have failed.
A normal saving throw has 4 degrees of success or failure.
Critical Failure(CF): When your roll is 10 or more less than the DC
Failure(F): When your roll is less than 10 lesser than the DC
Success(S): When you roll is less than 10 more than or the DC or equal to the DC.
Critical Success(CS): When your roll is 10 or more than the DC.
Ward is damage reduction for all damage except true damage. Like Armor, 1 Ward reduces 1 damage for every 10 damage done.
Resistance is flat 50% damage reduction, rounded down of the specified damage type.
Damage reduction is done by this order
Any flat damage reduction -> Armor -> Ward -> Resistance