Error code CS1612...

I’m getting an error cade at lines (7-9,36) about the fact that a field initializer cannot reference the nonstatic field, method, or property.
I tried to find the awnser over the internet but I tried everything but it all didn’t work.

using UnityEngine;
using System.Collections;

public class PickUp : MonoBehaviour {
   
    // The variables for the positions.
    float CharacterPositionX = Character.transform.position.x + 3;
    float CharacterPositionY = Character.transform.position.y + 3;
    float CharacterPositionZ = Character.transform.position.z + 3;
 
    // The Player and the tagged objects.
    public GameObject CarryableObject;
    public GameObject Character;
 
    void Start() {
        // The origin of the objects.
        CarryableObject = GameObject.FindWithTag("Carryable");
        Character = GameObject.Find("Character");
        // The code for determining the position (Put in note mode to deactivate but keep it).
        // CharacterPositionX = Character.transform.position.x + 3;
        // CharacterPositionY = Character.transform.position.y + 3;
        // CharacterPositionZ = Character.transform.position.z + 3;
  }
   
    void OnTriggerStay(Collider other) {
        if(Input.GetKeyDown("e")) {
            // The position relative to the character.
        CarryableObject.transform.position.x = CharacterPositionX;
        CarryableObject.transform.position.y = CharacterPositionY;
        CarryableObject.transform.position.z = CharacterPositionZ;
        // The rotation relative to the character.
        CarryableObject.transform.rotation = Character.transform.rotation;
        // The gravity.
        other.attachedRigidbody.useGravity = false;
        }
    }
}

This should help: