Learn the chess rules
The rules that actually cause arguments, explained properly.
En passant
The pawn capture that looks illegal but is not.
Castling
When you can, when you cannot, and the two rules people get wrong.
Stalemate
Why a completely winning position can end in a draw.
Board setup
Get the starting position right, step by step.
Where to start
If you already know how the pieces move, learn stalemate first. It is the rule that most often costs beginners a won game. En passant comes second, because it is the rule most often played incorrectly, and castling third, because its restrictions are widely misremembered.
Every guide here demonstrates the rule on a real board rather than a diagram, and each one links back to a playable board so you can try it immediately.