Some things about a character are relatively static and do not change as they advance in skills. These are represented as stats. If your character excersises a lot and bulks up, this should probably be represented as a change of characteristics (from slight to built for example), talk to your GM.
These stats have a default value of 0, and generally range from -10 to +10
These stats are sometimes rolled like a skill for things that are purely based on the stat (do you remember something, can you dead lift that rock, does someone find you attractive at first glance). These rolls have a target like skill rolls (though the target is often lower) and are often made with 2d10 5d4 or flat 10 checks because there is frequently little randomness in this kind of thing.
raw physical power, heavily dependent on how big you are. Skills may determine how well you use your strength, but if you want to use a big honking rifle or a gigantic sword, there is little substitute for just being beefy.
Weapons have a strength requirement to use effectively, and melee weapons and unarmed strikes damage is partially determined by strength.
Innate tendency to remember information, people, places, etc. A +10 memory is essentially photographic, anything you can generally reconstruct anything you were paying attention to at a reasonable level of detail.
Covers things like symmetry, bone structure, complexion, etc of that sort that are generally universally associated with attractiveness. Depending on the social norms and specific people you are interacting with different body types (athletic, slim, ...) may give effective bonuses or penalties on attractiveness. Attractiveness is generally rolled when you first meet someone to determine their initial reaction (obviously modulated by other factors that may predispose them for or against you). It also enables more flirtatious uses of social skills.
There is a stat for each pool, again 0 centered, these values are added to the indicated pool. Pool stats can range over a somewhat larger range
Height and weight are given a base value by your gender (and race if playing in a game with nonhumans) and are modified by your characteristics.
You can also have a size modifier on your pools, this is applied as a multiplier to all of your physical pools after other modifications, and also applies as a multiplier on all effort costs. This multiplier does not apply to damage received, so larger creatures are more durable. So for example, an ogre might have a size of 2, meaning all of their pools are twice as big, but so are their effort spends.