How it works?? Trouble getting it to work.

I recently downloaded this plugin from Woo Themes. I installed it and now what? According to one of the support staff at Woo it should display the sold out sign if a product is sold out. Is there a step I am missing that makes this plugin work? I see documentation for a widget and shortcode. Don’t need them, I don’t think. We have a simple store and want our clients to know when a product is out. Are there settings that make this work like in stock management? Some guidance would be appreciated.

Thanks,
Michael

https://wordpress.org/plugins/woocommerce-sold-out-products/