how to design buttons in unity code example

Example 1: unity gui button

if (GUILayout.Button("I am a regular Automatic Layout Button")){
    Debug.Log("Clicked Automatic Layout Button ");
}

if (GUI.Button(new Rect(10, 70, 50, 30), "I am a regular Button"))
    Debug.Log("Clicked Regular Button");
}

Example 2: how to declare an button in unity

using UnityEngine.UI;

public class PlayerDash : MonoBehaviour
{
public Button your_button;