How to make the character walk-jump and walk (and resize the collider when crouched) ?

I am new to unity and I wrote this code and I'm trying to make my character walk even when I press the keys: A S D. I only have an animation that moves forward. I want my character in 3d person, so maybe always moving forward can be fixed with: first turning around then walk (could this make it work or look better ?) (I don't know how to make the camera follow the character but not turing around with him tho). Also, I wish that my character could jump while walking. Now it responds very slow when I press the spacebar key. And last one: I try to resize the Capsule Collider when crouched but this code won't work. Maybe someone know how to fix one of this things? Please help :)

 using UnityEngine;
     using System.Collections;
     
     [RequireComponent(typeof(Animator))]
     [RequireComponent(typeof(Rigidbody))]
     [RequireComponent(typeof(CapsuleCollider))]
 
 public class ActionsC : MonoBehaviour
     {
         private Animator animator;
         CapsuleCollider m_Capsule;
     
         float m_CapsuleHeight;
         Vector3 m_CapsuleCenter;
     
         private void Start()
         {
             animator = GetComponent<Animator>();
          
             // for capsule collider resizing
             m_Capsule = GetComponent<CapsuleCollider>();
             m_CapsuleHeight = m_Capsule.height;
             m_CapsuleCenter = m_Capsule.center;
         }
         private void Update()
         {
             Walk();
             Run();
             Sitting();
             Jump();
             Aiming();
         }
 
         //  idle animation
         public void Stay() 
         {
             animator.SetBool("Aiming", false);
             animator.SetFloat("Speed", 0f);
         }
         public void Walk()
         {
             float xMov = Input.GetAxisRaw("Horizontal");
             float zMov = Input.GetAxisRaw("Vertical");
     
             if (Input.GetKey(KeyCode.W))
             {
                 animator.SetBool("Aiming", false);
                 animator.SetFloat("Speed", 0.5f);
             }
             // I don't have animation for these so idk what to do
             else if (Input.GetKey(KeyCode.W))
             {
                 
             }
             else if (Input.GetKey(KeyCode.A))
             {
     
             }
             else if (Input.GetKey(KeyCode.D))
             {
     
             }
             else Stay();
         }
         public void Jump()
         {
             if (Input.GetKeyDown(KeyCode.Space)){
                 animator.SetBool("Squat", false);
                 animator.SetBool("Aiming", false);
                 animator.SetTrigger("Jump");
                 rigid.AddForce(Vector3.up * 100.0f);  
             }
             // walk and jump
             else if (Input.GetKeyDown(KeyCode.W))
             {
                 if (Input.GetKeyDown(KeyCode.Space))
                 {
                     if (Input.GetKeyDown(KeyCode.LeftShift)) { speed = 40.0f; }
               
                     animator.SetBool("Squat", false);
                     animator.SetFloat("Speed", 0f);
                     animator.SetBool("Aiming", false);
                     animator.SetTrigger("Jump");
                     rigid.AddForce(Vector3.up * 100.0f);
                 }
             }
         }
         //crouching
         public void Sitting()
         {
             if (Input.GetKeyDown(KeyCode.C)){
                 animator.SetBool("Squat", !animator.GetBool("Squat"));
                 animator.SetBool("Aiming", false); 
             }
         }
         // trying to scale the collider when crouched
        void ScaleCapsuleForCrouching(bool crouch)
         {
             if (Input.GetKeyDown(KeyCode.C))
             {
                 if (Input.GetKeyDown(KeyCode.C)) return;
                 m_Capsule.height = m_Capsule.height / 2f;
                 m_Capsule.center = m_Capsule.center / 2f;
             }
         }
     }