How can I use index while iterating over JSONArray in handlebar?

I am trying to show the details of the adultJsonArr in different and I want to get it saved on action without going into writing lengthy code.

I'm not getting idea of how to use the index while iterating, I tried as mentioned in line no 5 but didn't work( @index also couldn't do job for me).

Any suggestion on how to save the changes made to the input in the adultJsonArr

1.<form> 
2.   
3.    <div id="adult_form">
4.      Adult: 
5.      <input type="text" value="" required> 
6.      <input type="dob" value="">
7.      <input type="text" value="" required>
8.    </div>
9.   
10.  <div >
11.     
12.  </div>
13.</form>