How to manage Timeline?

Turn off 'play on Awake' on the PlayableDirector. Then, have a script something along the lines of the following:

Code (CSharp):

1.  
2. public class MyBehaviour : MonoBehaviour
3. {
4.     public PlayableDirector playableDirector;
5.     public bool conditionMet {get;set;}
6.    
7.     void Update()
8.     {
9.         if (conditionMet && playableDirector != null)
10.         {
11.             conditionMet = false;
12.             playableDirector.Play();
13.    
14.         }
15.     }
16. }

There are of course many variations - how the condition is met, the playableDirector might be on the same gameObject as this script - but hopefully this gives the general idea.