maintainn-cmb-1.php

<?php
/**
 * Register Team Members metabox as repeatable group fields.
 */
function maintainn_team_members_metabox() {
	$prefix = '_maintainn_team_';

	$cmb_group = new_cmb2_box( array(
		'id'           => $prefix . 'metabox',
		'title'        => __( 'Team Members', 'maintainn-demo' ),
		'object_types' => array( 'page' ),
		'show_on'      => array( 'key' => 'page-template', 'value' => 'page-templates/full-width.php' ),
	) );

	$group_field_id = $cmb_group->add_field( array(
		'id'          => $prefix . 'meta',
		'type'        => 'group',
		'description' => '',
		'options'     => array(
			'group_title'   => __( 'Member', 'maintainn-demo' ),
			'add_button'    => __( 'Add Another Member', 'maintainn-demo' ),
			'remove_button' => __( 'Remove', 'maintainn-demo' ),
			'sortable'      => true
		)
	) );

	$cmb_group->add_group_field( $group_field_id, array(
		'name' => __( 'Fullname', 'maintainn-demo' ),
		'id'   => 'fullname',
		'type' => 'text'
	) );

	$cmb_group->add_group_field( $group_field_id, array(
		'name' => __( 'Position', 'maintainn-demo' ),
		'id'   => 'position',
		'type' => 'text',
	) );

	$cmb_group->add_group_field( $group_field_id, array(
		'name' => __( 'Photo', 'maintainn-demo' ),
		'id'   => 'photo',
		'type' => 'file',
		'options' => array(
			'url' => false
		)
	) );
}
add_action( 'cmb2_init', 'maintainn_team_members_metabox' );