Armor protects you from melee attacks and projectiles. More armor will reduce incoming damage, but could also slow you down from bulk.
Each attack has a Penetration value (or P-Value). If the P-Value of the attack is equal to or greater than the Armor Value, it will do 100% of the rolled damage value. For each point that the P-Value is less than the Armor Value, that rolled damage will be mitigated by up to 20%.
Bullets can also have an Expansion Damage (for rounds like hollow points). If the P-Value is equal to or greater than the Armor Value, 100% of the Expansion Damage is applied. If the P-Value is less than the Armor Value, no Expansion Damage is applied.
The starting CON (Constitution or hit points) of your Ranger. When your CON reaches 0, you will go unconscious.
How resistant this character is to gas and stinky cheese.
Your Rangers current Level or rank. As you progress through the Wasteland, you'll earn Experience Points (XP) that will increase your Level.
Max Water Carry
The maximum amount of water that can be carried for use on the World Map. When you visit an Oasis, you will have the option to refill your cannisters. It's probably a good idea...
Y'know, I really don't have a clue what this does.
The Perception Radius is the maximum distance that you are able to perceive things around you.
When travelling around the World Map, having a higher Radiation Protection value will help shield you from dangerous radiation clouds left over from when the bombs fell. Find or purchase better Radiation Suits to take less damage from radiation clouds.
How fast this character runs.
How fast someone moves while sneaking.
How fast this character walks.