Entanglement allows a player to create non-local correlations. If White entangles their Queen with Black’s Knight, then measuring the Queen’s position forces the Knight’s position. Skilled players use this to force unfavorable collapses for the opponent.
You cannot plan a linear sequence of moves (e.g., "I go here, he goes there, I checkmate"). Instead, you must think in branching possibilities: "If my Knight collapses to square A, I will be safe. If it collapses to square B, I lose my Queen."
A piece can exist in two squares simultaneously. When you make a "quantum move," you aren't just moving a piece; you are splitting its reality.