Planets & Starships
There are five slots armor can take up: head, chest, legs arms, & feet.
Some creatures have extra body parts like tails or wings and have additional slots for them. They can equip armor pieces for those slots if they are proficient in that armor weight class.
Your total AC is base 10 plus the total AC gained from all the armor pieces.
If the majority of your armor is light or unarmored, you may add your DEX modifier to your total AC.
If the majority of your armor is medium, you may add your DEX modifier up to 2 to your total AC.
If the majority of your armor is heavy, you do not add your DEX modifier to your total AC.
If the majority of your armor gives you disadvantage on stealth checks, you have disadvantage on stealth checks. If not, you may perform stealth checks normally.
Some classes have unarmored bonuses. They're allowed to wear up to one armor piece if they are proficient in that armor weight class.
These are special armor pieces that all classes are proficient in. They can allow creatures to survive in hostile environments, increase strength, even fly. Classes like monks still benefit from their unarmored bonus when wearing these sets unless stated otherwise.