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

Code Example 1

Invoke("functionname", seconds);
// this is for C#

Code Example 2

void start()
StartCoroutine(Text());

IEnumerator Text()  //  <-  its a standalone method
{
	Debug.Log("Hello")
    yield return new WaitForSeconds(3)
    Debug.Log("ByeBye")
}

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