"How does it work" Part 1: Bullet Impact

"How does it work" Part 2: Character Skills

"How does it work" Part 3: Experience Level

"How does it work" Part 4: Chance-to-Hit

"How does it work" Part 5: Melee Combat Chance-to-Hit

"How does it work" Part 6: Auto-Resolve

"How does it work" Part 7a: Levelling Up

"How does it work" Part 7b: Gaining Chances to Level Up

"How does it work" Part 8: Skill Checks

"How does it work" Part 9: Relationships 

"How does it work" Part x: Suppression

This guides were created by Headrock, if you have any questions you may contact him on Bear's Pit. (Link)