[WordPress] An example for using templates, partials, and helper functions in the Dashboard of WordPress.

1-meta-box-tabs.php

<?php
/**
 * Template for rendering the meta box.
 *
 * @since    1.0.0
 */
?>
<div id="meta-box-tabbed-navigation">

	<h2 class="nav-tab-wrapper current">
		<a class="nav-tab nav-tab-active" href="javascript:;">Alpha</a>
		<a class="nav-tab" href="javascript:;">Beta</a>
		<a class="nav-tab" href="javascript:;">Gamma</a>
	</h2>
	
	<?php // More To Come... ?>
	
</div><!-- #meta-box-tabbed-navigation -->

2-meta-box-includes.php

<?php
/**
 * Template for rendering the meta box.
 *
 * @since    1.0.0
 */
?>
<div id="meta-box-tabbed-navigation">

	<h2 class="nav-tab-wrapper current">
		<a class="nav-tab nav-tab-active" href="javascript:;">Alpha</a>
		<a class="nav-tab" href="javascript:;">Beta</a>
		<a class="nav-tab" href="javascript:;">Gamma</a>
	</h2>
	
	<?php

		// Include the partials for rendering the tabbed content
		include_once( 'partials/alpha.php' );
		include_once( 'partials/beta.php' );
		include_once( 'partials/gamma.php' );

	?>
	
</div><!-- #meta-box-tabbed-navigation -->

3-alpha-partial.php

<?php
/**
 * Partial for rendering the view of the 'Alpha' meta box.
 *
 * @since    1.0.0
 */
?>
<div id="alpha-container">

	<?php $amount = acme_get_financial_post_meta( 'acme_financial_data' ); ?>
	<input type="text" id="acme_financial_data" name="acme_financial_data" value="<?php echo $amount; ?>" />

</div><!-- #alpha-container -->

4-financial-post-meta.php

<?php

/**
 * Retrieves financial post meta data based on the specified key. Formats the number
 * that is stored in the database as an integer as a currency.
 *
 * @since    1.0.0
 *
 * @param    string    $key    The meta key from which to pull the data.
 * @return   string            The value of the formatted string.
 */
function acme_get_financial_post_meta( $key ) {

	$value = get_post_meta( get_the_ID(), $key, true );
	if ( 0 < strlen( trim( $value ) ) ) {
		$value = number_format( $value, 2, '.', ',' );
	}

	return $value;

}