The code below is an example of a simple countdown timer. The code would need modified to be useful in the LevelManager. The timer uses a co-routine that pauses 1 second between each repeat.
using System.Collections;using UnityEngine;using UnityEngine.UI;publicclassCountDown : MonoBehaviour {publicint timeLeft =60; //Seconds OverallpublicText countdown; //UI Text ObjectvoidStart () {StartCoroutine("LoseTime");Time.timeScale=1; //Just making sure that the timeScale is right }voidUpdate () {countdown.text= (""+ timeLeft); //Showing the Score on the Canvas }//Simple CoroutineIEnumeratorLoseTime() {while (true) {yieldreturnnewWaitForSeconds (1); timeLeft--; } }} //end class