update order review without redirect to page checkout

I change form payment WooCommerce to multistep. I integrate the short code ‘[woocommerce_checkout]’ in my custom template . I want to update order without redirect to page "order" .On click button "Reserve" the order should be ready , then passed to form checkout fill fields then step method payment .

<fieldset id="step-3">
   <?php

      define('WOOCOMMERCE_CHECKOUT', true);
      echo do_shortcode('[woocommerce_checkout]');

   ?>

</fieldset>