Hit Points (hp) represent how much damage you can take before you fall unconscious and start to take serious damage. When your hit points reach 0 your body goes into shook. To stop this you may attempt a Will save to stay awake for one more round. Also when at 0 hit points all subsequent damage is taken as TERRIBLE LIFE THREATENING INJURIES.
HP = CON * 2 + STR +1 per level
These saves measure your ability to stand up to physical punishment or attacks against your vitality and health. Apply your Constitution modifier to your Fortitude saving throws.
These saves test your ability to dodge area attacks. Apply your Dexterity modifier to your Reflex saving throws.
These saves reflect your resistance to mental influence as well as many magical effects. Apply your Wisdom modifier to your Will saving throws.
You must first see if you hit your opponent before determining if you deal damage to it. Rolla d20 and all the bonuses that apply.
Usually you roll an attack roll to determine if you hit an opponent and then you roll for damage. There is no such thing as critical hits or auto-fails on 1’s. If in space, there is no such thing as maximum range, you just have a really small chance of hitting if trying to hit something past your maximum range…
Humans like to accelerate projectiles to deal damage, they also have armor which is effective at stopping these kinds of weapons. In the past they have also been known to use sharp or blunt objects. Humans have somewhat effective methods of reducing the amount of harm caused by these weapons. Note: Melee weapons bypass 50% of the DR provided by any armor.
There are other methods of dealing damage, such as radiation, freezing, heating, vibrations etc…