The "Woo Checkout" section contains two elements: "Checkout" and "Order tracking". The "Woo Checkout" can be used just on a Woocommerce checkout page. When the elements are dropped on a different page, will be displayed a red notification providing instructions to set the "Checkout" page.
The "Checkout" page can be set from WP Admin > Woocommerce > Settings > Checkout.
Once the "Checkout" page is set properly, the "Checkout" element from the "Live Composer WooCommerce Integration" will be displayed in this way: