Ok, attacks need two rolls. To roll use this tool:
http://invisiblecastle.com/rolldice.py, you will find additional instructions there.
Marksmanship roll is 1d100, if you have a marksmanship of 80 and you roll result is above this number you will miss the target, if your result is 80 or below 80 you have hit the target.
Damage roll depends on the weapon max damage. If the weapon has a max damage of 40 the roll will be 1d40, and if the weapon has a min damage of 12, every result below 12 will count as 12 points of damage. Enemy soldiers have 40 hits points each at the beginning.
Taking damage: Depending on the enemy you can receive a certain amount of damage when an enemy attacks, this damage will decrease your hit points. Standard enemy attacks at the beginning of the game are 11-22 one shot per turn. You will have to roll these as well when you receive an enemy attack.
All hit points lost during combat cannot regenerate unless you use a stimpack or you receive medical care. Each stimpack regenerates 25 hit points when used, and each player will have two stimpacks to begin with, use them wisely.
Cover: Yes I know I wrote something about it before but this is more simplified. When receiving an enemy attack you can decide to return fire or to take cover behind an obstacle to avoid damage. If you use the turn to take cover you cannot attack any enemy during the entire turn. Most times the team will be in a position where you can take cover behind obstacles unless specified otherwise.
