Vector3 does not contain a constructor that takes 4 arguments

Hi, I have been learning unity for about two days now. I was stuck on the rb = GetComponet< Rigidbody>(); for a little while but now i have a new error with Vector3 and the Mathf.Clamp variables.

I don't know what i am looking for to fix this. it is probably very obvious/simple.

 public class Boundary
 {
     public float xMin, xMax, zMin, zMax;
 }
 
 public class PlayerController : MonoBehaviour
 {
 
     public float speed;
     public Boundary boundary;
     
      public Rigidbody rb;
      void Start()
     {
         rb = GetComponent<Rigidbody>();
     }
     void FixedUpdate()
     {
         float moveHorizontal = Input.GetAxis("Horizontal");
         float moveVertical = Input.GetAxis("Vertical");
 
         Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
         rb.velocity = movement * speed;
         rb.position = new Vector3
             (
             Mathf.Clamp(rb.position.x, boundary.xMin, boundary.xMax),
             0,0f,
             Mathf.Clamp(rb.position.z, boundary.zMin, boundary.zMax)
             );
 
     }
 }