Getting Started: Ability Scores & Modifiers

The basics of the whole game, ability scores are the stats that govern every character and thing your characters are likely to do going forward with few exceptions. If you want to attack a monster with your sword, your Strength (Str) ability score is factored. Your Bard trying to remember what the hell a Lich is? That knowledge check uses Intelligence (Int) to figure it out. Your Rogue trying to barrel roll out of a massive explosion? That's a Reflex save (Ref) which uses your Dexterity (Dex). In short, every skill check, attack roll, and save you will make is effected by these numbers, and therefore it behooves me, to try and walk you through these stats as quickly and (hopefully) painlessly as possible. So, without further adieu, lets get to it.

WTF is an Ability, and how do you Score it?

• An ability is one of the 6 basic stats that effect in one way or another, every part of your character sheet. These Abilities are...
• Strength (Str)
• Dexterity (Dex)
• Constitution (Con)
• Intelligence (Int)
• Wisdom (Wis)
• Charisma (Cha)
• Now, each of these stats has a number associated with it that is determined as part of character creation. With us, that is through point buy but with every table this can be a little different and isn't really the point of this discussion. The important thing here to remember is that THESE are your 6 abilities and they are represented with a number called an Ability Score. 
• Ability Score: Now, with each ability you have 2 numbers, an Ability Score and an Ability Modifier. The Score is the bigger number, usually somewhere between 9-16 or so at start but with numbers being as low as around a 6-7 to a starting high of 18-20. This number is largely superfluous and is used to determine your Ability Modifiers, which is what actually modifies your rolls. That said, make sure your Score is kept up to date and that you commit it to memory. There are abilities that will effect it, and changes to your Score will effect the modifiers it gives. 
• Ability Modifiers: The ability modifier (as mentioned above) is the modifier you get from your ability score. These are flat numbers that are added to every attack roll, damage (dmg) roll, skill check, save, and general formula your character creates in some form or another. Not every Ability Mod is applied to every roll, but every roll is modified somehow. Know these numbers! If the statement above isn't obvious, they are probably the most essential numbers you'll have on your sheet, and you do not want to be the guy/gal who's gotta pause the game to look up what your mod is for this weird new circumstance. 
• (House Rule) Extra Dice: For those of you who play game with me and don't just read my lovely blog, we do Ability modifiers a bit differently. Instead of gaining a flat ability modifier from your Ability Score as you do in the base game, you are instead granted an extra die you add to your rolls. These dice follow a similar scaling to those in the base game and replace those flat mods. When determining what dice your Ability Score gives, just look at the mod and find the die with an average equal to that number and you're set. So, a +2 becomes a +1d4, a +3 becomes a +1d6, etc. 
• (Protip) The Math: So, the modifiers themselves and what Scores grant them are listed in the book but if you are someone who doesn't like memorizing what Ability Modifier goes with every Ability Score here are a few quick ways to learn this math. Use whichever you like, I have used just about every one of them at some point or another, if you find one that works with you I hope it helps. 
• Memorize a single stat, know the Math up: My original method and default go to, under this method, all you have to do is just learn one of the ability mods like say, an Ability Score 10, and then do the math from there. As a rule of thumb, each shift of 2 to the Ability Score shifts your mod by 1 in the same direction. So, if you have a Score of 10 which gives a +0 mod, and you increase the score by 2 to 12, your mod will go up by 1 to +1. Get good at this and I've found that you start to memorize those numbers and figure out what your mod is pretty quickly, an essential once you and your party start throwing around stat buffing spells and buying armor and other boosting equipment. 
• The Formula: For those who just like math and formula better, then you might be happy to know there is a formula for figuring out what your Ability Mods are. I've got it below and in a pinch this is another fast way to figure out your modifier if the above doesn't mesh with how you learn. 
• (Ability Score-10)/2=Ability Modifier

Next Up, a discussion of the individual Abilities and what they mean. Seemed better to break these up than have this one post last forever.