How do I store my recorded notes in a json-file?

I am making a rhythm-game and I've made a scene where you can record your notes that you've played to a song and it is working just fine and it keeps a list of every note played in a List<> of something called a "Row", basically, it is just checking for which key was pressed and then setting a value to true in that "Row".

But now I want to be able to store my notetracks, but I'm not sure how to do so. I have used PlayerPrefs in the past but not for stuff like this and I don't think it would be optimal either, so I'm thinking of making a Json-file but I'm not sure how I would do that.

Here's the Row-class:

 using UnityEngine;
 using System.Collections;
 
 [System.Serializable]
 public class Row {
 
     public float timestamp;
     public bool b1;
     public bool b2;
     public bool b3;
     public bool b4;
     public bool b5;
 
 
     public Row(float ts, bool a, bool s, bool d, bool f, bool g)
     {
 
         timestamp = ts;
         b1 = a;
         b2 = s;
         b3 = d;
         b4 = f;
         b5 = g;
 
 
     }
 
 }

And this is how it is recorded:

     if (Input.GetKeyDown (KeyCode.A) && recording == true) {
 
             float currentTime = Mathf.Round(timer * 10f) / 10f;
             createdRows.Add (new Row (currentTime, true, false, false, false, false));
 
         }