Once you know how we talk about ranks, files and squares in Chess, we can start discussing how each piece is moving. The Queen, the Rook, the Bishop, the Knight and the pawn all have their specific way of moving, but we are going to start with the most important piece of all: the King.
The reason why the King is so important in Chess is that all your efforts will be directed towards the enemy King while your own King has to be safe enough.
This is all you have to know about how the King moves, for the moment ! Once you know how all the pieces are moving, you can check how to capture pieces, how to castle, and the rules driving checkmate and stalemate.
If you are learning all the rules of Chess, you should probably look at how the Rook moves next.