How to make 3rd person stafe around target?

After a LOT of time. I was able to move the character forward towards the direction of the mouse. But, when i press other directional buttons (right, left, back) the characters turns to that direction and moves forward in that direction. But, I want to be able lock on to a target and strafe and walk backwards around that but only move forwards in the direction of mouse. ( witcher 3 combat, movement style) IDK how to did this because i am beginner and i did all this from a tutorial. Here is my Movement Script:

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

public class playercontrollerScript : MonoBehaviour

{

private Animator anim;

public float speed = 3.5f;

public float animspeed = 2.0f;

Vector2 input;

public Transform player;

public float turnSmoothTime = 0.2f;

float turnSmoothVelocity;

public float speedSmoothTime = 0.1f;

float speedSmoothVelocity;

float currentSpeed;

Transform cameraT;

// Start is called before the first frame update

void Start()

{

anim = GetComponent();

cameraT = Camera.main.transform;

}

void Update()

{

anim.speed = animspeed;

// Move

Vector2 input = new Vector2(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical"));

Vector2 inputDir = input.normalized;

if (inputDir != Vector2.zero)

{

float targetRoation= Mathf.Atan2 (inputDir.x, inputDir.y) * Mathf.Rad2Deg + cameraT.eulerAngles.y;

transform.eulerAngles = Vector3.up * Mathf.SmoothDampAngle(transform.eulerAngles.y, targetRoation, ref turnSmoothVelocity, turnSmoothTime);

}

float targetSpeed = (speed) * inputDir.magnitude;

currentSpeed = Mathf.SmoothDamp(currentSpeed ,targetSpeed, ref speedSmoothVelocity, speedSmoothTime);

transform.Translate(transform.forward currentSpeed Time.deltaTime, Space.World);

float animationSpeedPercent = (3.5f) * inputDir.magnitude;

anim.SetFloat("VelY", animationSpeedPercent, speedSmoothTime, Time.deltaTime );

}

}

Any tips?