save-custom-form.php

<?php
/**
 * Save custom form "sample_form".
 *
 * @return void
 */
function my_custom_ap_form() {
	$form = anspress()->get_form( 'sample_form' );

	// Get all sanitized values.
	$values = $form->get_values();

	// Check nonce and is valid form.
	if ( ! $form->is_submitted() ) {
		echo __( 'Holla, you trying to cheat!' )
		return;
	}

	// you can start saving your data here.
}
add_action( 'init', 'my_custom_ap_form' );