Would someone please summarize char gen and action system in PF2, for what is known? Thanks
Character generation (from the playtest): Based on choosing Ancestry (previously known as race), Background, and Class. Some of these contain one or more sub-choices (e.g. which of these four 1st level abilities do you want?). Those three largely determine stats as well - at each stage, you get a number of stat boosts (some fixed, some you get to choose, but no stage can double up on the same stat) and sometimes stat flaws, and at the end you get another round of customizing stat boosts.
So let's say you want to play a dwarf monk who used to be a sailor. You'd choose:
Ancestry: Dwarf. As a dwarf, I have speed 20 ft, and I get ability boosts to Constitution and Wisdom as well as a free one which I put in Dex. I also get an ability flaw to Charisma, and I get Darkvision. I choose the heritage Ancient-Blooded (which gives me the ability to use a reaction to get +2 to a save against a magic effect, but reduces my ability to use magic items), and the ancestry feat Mountain Roots (which makes me hard to shove, trip, or otherwise push around).
Background: Sailor. This gives me two ability boosts: one to Strength or Dexterity (I choose Dexterity), and one free (I choose Constitution). I also get the skill feat Underwater Marauder, and training in the Sailor Lore skill (which means I know sailing-related stuff and can make money working as a sailor).
Class: Monk. This gives me a whole bunch of stuff: 10+Con modifier hp, an ability boost to Strength or Dexterity (I choose Dex), Expert proficiency in all three saves (so my bonus would be +2+level+stat) as well as unarmored defense (which means my unarmored AC is 12+level+Dex), trained proficiency in unarmed attacks (so my attack bonus is +1+level+stat), trained proficiency in Perception and in a bunch of skills, and I get to deal 1d6+Strength modifier damage with unarmed attacks. I also get Flurry of Blows, which once/round lets me make two attacks as a single action, and they are combined for the purposes of overcoming resistances and such. Finally, I get to choose a 1st level monk feat - the playtest offered 7 to choose from.
Discretionary: At this stage, I distribute an additional four ability boosts (no more than one per ability). I'll put them in Strength, Dexterity, Constitution, and Wisdom, and then sum up my stats: 10, +2 per ability boost, -2 per ability flaw. That gets me Str 16, Dex 18, Con 16, Int 10, Wis 14, Cha 8.
Final stuff: Buy gear for 150 sp (A PF2 silver piece is about the same as a D&D gold piece), finalize all other calculations (skill bonuses, etc), deal with details beyond the numbers.
At later levels, a lot of the heavy lifting is done by class feats rather than class features. Class feats are special abilities you can choose from your class's list every other level, sort of like the way rogues work in PF1. Fixed class features mostly (but not exclusively) give you higher proficiency levels with various things at higher levels.
This is all based on the playtest rules, and the details will probably change in the final version (for example, they've mentioned that proficiency levels will double their effect, so Expert unarmored defense will give AC 14+level+Dex). But these are the basics.
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Actions are fairly simple. On your turn, you can take three actions - no standard/move/swift/full-round actions, but three actions. Doing some things require more than two actions - this is called an "activity". For example, many spells take two actions to cast (one for the verbal component and one for the somatic). One action that requires a bit of special attention is Strike, which lets you make an attack against a foe. Your second attack in a round is at -5, and your third and possible subsequent ones are at -10 (certain weapons have the Agile trait, which reduces the penalty to -4/-8 instead). So if I really wanted to go to town on someone as a monk, I could use Flurry of Blows for my first action (making one regular attack and one at -4, because Fist is an agile weapon), then Strike for my second action (at -8), and Strike again for my third (also at -8). Usually, you will not be making attacks at -8 or -10, because you will almost certainly have something more useful to do.
There are also two more types of actions: Reactions and Free Actions. Both are done in response to triggers, and can be taken on both your own and others' turns. The difference is that you only get one reaction in between each of your own turns (it resets at the start of your turn), whereas you can do as many free actions as there are opportunities. It also bears mentioning that Attack of Opportunity is now mostly a fighter thing, so moving from one opponent to another is usually no big deal.