Doesn't that mean all 20s would also be crits by default?
Signed, Someone who has never played D&D before
To attack an enemy/target, a person has to roll a 20 sided dice. combatants has a amor stat. If your Dice roll exceeds that, the attack hits. Then you roll an attack dice. Which means you roll any from a 4 sider dice to an 8 sider dice depending on the weapons you are equipped with. A critical gives you double damage off the attack dice rool.
To start combat: 1. Roll a 20 sider dice. 2. roll attack dice.
If the dice roll from the 20 sider dice is a 20, you get a critical chance. Then you roll to confirm the critical.
Oh shit, you gotta, gotta get that terminology right. The first d20 roll is to attack, the second dice roll is for damage.