Check out example codes for "unity load scene". It will help you in understanding the concepts better.

Code Example 1

using UnityEngine.SceneManagement;

//Put this in whenever you want to load a scene
SceneManager.LoadScene("Scene name");

Code Example 2

using UnityEngine.SceneManagement;

int buildIndex = 0;
//Load the scene with a build index
SceneManager.LoadScene(buildIndex);

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