The finished Player Controller script for Unity Roll-a-Ball Tutorial with jumping and score keeping

BallControl_Jump.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class PlayerController : MonoBehaviour {

	public float speed;
	public float jumpHeight;
	public Text countText;
	public Text winText;
	public int numPickups;

	private Rigidbody rb;
	private int count;

	void Start() 
	{
		rb = GetComponent<Rigidbody>();
		count = 0;
		SetCountText();
		winText.text = "";
	}
	
	void FixedUpdate () 
	{
		float moveHorizontal = Input.GetAxis("Horizontal");
		float moveVertical = Input.GetAxis("Vertical");

		Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

		rb.AddForce(movement * speed);

		if (Input.GetKeyDown("space"))
		{
			Vector3 jump = new Vector3 (0.0f, jumpHeight, 0.0f);
			rb.AddForce (jump);
		}
			

	}

	void OnTriggerEnter(Collider other) 
	{
		if (other.gameObject.CompareTag("Pick Up"))
		{
			other.gameObject.SetActive(false);
			count++;
			SetCountText();

		}
    }

    void SetCountText ()
	{
		countText.text = "Count: " + count.ToString ();
		if (count >= numPickups) 
		{
			winText.text = "You win!";
		}
	}
}

@Galaxy-EM6
I think you may have found it out by now and I probably don't know much more than you but, In the unity editor have you clicked save asset inside of your Input actions ? If so, after that you need to select your Input actions in the Assets and tell it to generate a c# class, you can leave the fields blank, then press apply. And as far as the code goes I don't see any reason for it to not work except that currently your speed is set to 0 (unless you changed it in the editor) and your player character might not have a rigidbody or the rigidbody is part of the child. Also, most importantly, make sure there is a player Input component with the Input actions on it attached to the game object.

I used your code and that was the only thing I needed to do.