JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/stickyfill/1.1.4/stickyfill.min.js"></script>
<form class="form">

  <!-- row -->
  row 1
  <div class="form__row"> 
  
    <!-- item -->
    <div class="form__item">
     <div class="form__group">
      <select class="form__select" name="select-child" required>
				<option value="">Select 1 *</option>
				<option value="1">option 1</option>
				<option value="2">option 2</option>
				<option value="3">option 3</option>
			</select>
      </div>
      <div class="form__group">
      <select class="form__select" name="select-adult" required>
				<option value="">Select 2 *</option>
				<option value="1">option 1</option>
				<option value="2">option 2</option>
				<option value="3">option 3</option>
			</select>
      </div>
      <div class="form__group">
        <label class="form__radio">
            <input type="radio" name="state" value="yes"><span>Yes</span>
        </label> 
        <label class="form__radio">
            <input type="radio" name="state" value="no"><span>No</span>
        </label> 
      </div>
    </div>
    <!-- item -->
    
    <!-- item -->
    <div class="form__item">
     <div class="form__group">
      <select class="form__select" name="select-child-2" required>
				<option value="">Select 1 *</option>
				<option value="1">option 1</option>
				<option value="2">option 2</option>
				<option value="3">option 3</option>
			</select>
      </div>
      <div class="form__group">
      <select class="form__select" name="select-adult-2" required>
				<option value="">Select 2 *</option>
				<option value="1">option 1</option>
				<option value="2">option 2</option>
				<option value="3">option 3</option>
			</select>
      </div>
      <div class="form__group">
        <label class="form__radio">
            <input type="radio" name="state-2" value="yes"><span>Yes</span>
        </label> 
        <label class="form__radio">
            <input type="radio" name="state-2"...

SCSS

.form{
  
  &__row{
    display: flex;
    border: 1px solid #ccc;
  }
  &__item{
    padding: 15px;
  }
  &__group{
    margin-bottom: 10px;
  }
  
  &__select{
    width: 100%;
    display: block;
  }
  
}

JavaScript

// FormData
//   row 1
//   item 1
//   row[0][names][0][select-child]: 1
//   row[0][names][0][state]: yes
//   row[0][names][0][select-adult]: 1 

//   item 2
//   row[0][names][1][select-child]: 1
//   row[0][names][1][state]: no
//   row[0][names][1][select-adult]: 1

//   row 2
//   item 1
//   row[1][names][0][select-child]: 1
//   row[1][names][0][state]: yes
//   row[1][names][0][select-adult]: 1