Particle emission error

I used the particle callback asset and I tried to modify this code

 public ParticleSystem[] water;
 
 
 
  // Update is called once per frame
     void Update () {
 
 
         if (Input.GetButton("Fire1"))
         {
 
             if (!water[0].isPlaying)
             {
                 for (int i = 0; i < water.Length; i++)
                 {
                     water[i].Play();
                 }
             }
         }
         else
         {
             if (water[0].isPlaying)
             {
                 for (int i = 0; i < water.Length; i++)
                 {
                     water[i].Stop();
                 }
             }
         }
 
     }

How do I get this code to work?