It's completely okay to feel overwhelmed when trying something new, such as playing Dungeons and Dragons. Remember, it doesn't have to be perfect right away. As for calculating armor class, I can certainly clarify it for you! In DnD 5e, Armor Class (AC) is primarily determined by the armor your character is wearing. The base AC is 10, plus the armor's designated bonus, plus your character's Dexterity modifier (if applicable).