How the Rook Moves and Captures
The Rook moves horizontally and vertically any number of squares, forwards or backwards. In the diagram the Rook can move to any of the highlighted squares.
In this diagram the Rook now has less choice of squares to which it can move because the other White pieces block its path. It can now only move to the highlighted squares.
If an enemy piece is standing on a square to which the Rook can move, it can be captured. In the next diagram, White is able to capture the Bishop with her Rook. She does this by removing the Bishop from the board and placing the Rook on that square instead.
The Rook captures the Bishop and claims the square for itself!