First person camera strafe movement

Hi,
I’m still trying to build a physics enabled FPS movement with puzzles. Forward and backward movement is working but i can’t figure it out how to calculate left-right vector calculations.
i found how to calculate left vector on web but i’m not sure how to apply this with puzzles.

var vectorUp = new THREE.Vector3(0, 1, 0);
// Left vector
var coefficient = Player.SPEED * delta * this.q;
this.v.copy(new THREE.Vector3().crossVectors(vectorUp, cameraLookVector).normalize().multiplyScalar(coefficient));

var coefficient = Player.SPEED * delta * this.q;

// Right vector
this.v.copy(new THREE.Vector3(1, 0, 0).applyQuaternion(camera.quaternion).multiplyScalar(coefficient));

Three.JS FPS Controls Strafing Left and Right

Help…