It sounds like it is working correctly. The plugin will allow you to sell and use the gift cards however with just the free plugin, you will need to create the gift card manually. The receipt will have the Gift Card data on the card.
If you are wanting to have the card created automaticlly, you would need to add my premium extension that creates the card. You can get it at the link below.
https://wp-ronin.com/downloads/auto-send-email-woocommerce-gift-cards/
Ryan