move a player at specific distance to road lanes

I am currently creating a five lane highway style that has the character gameobject move to the next right lane on on right button click and the previous left lane on left button click

the following is my code;

            public class PlayerMotor : MonoBehaviour {

 
 private Vector3 moveVector;


 private float speed = 5.0f; 
 private float horizontalspeed = 0.8f;

          void Update () {
     //X  Left an d Right

     moveVector.x = Input.GetAxis ("Horizontal") * horizontalspeed;

     if (Input.GetMouseButton (0)) {
         if (Input.mousePosition.x > Screen.width / 2)
             moveVector.x = +speed;
         

         

         else
             moveVector.x = -speed;
         
     }
                     }
                   }

Please help!!

Im new to unity..

Thanks..

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