Adding Shipment Tracking

Hello,

I’ve installed the WooCommerce Shipment Tracking plugin on my website. I want to add this tracking information automatically in my Woocommerce mails. I’m using your Email Template Customizer for WooCommerce plugin for this. How can I add those tracking info? I already tried to add “{{order-_wc_shipment_tracking_items:tracking_number}}” to my email, but it doesn’t work. Could you please help me with this?