Theme fully supports free WooCommerce plugin. Make sure you install it and activate it upon installation. Once you do you will be promoted to run the initial setup.
You can learn more about WooCommerce here https://docs.woocommerce.com/documentation/plugins/woocommerce/
It is a good idea to import WooCommerce Dummy Date to see how things works, learn more here https://docs.woocommerce.com/document/importing-woocommerce-dummy-data/
If you just installed the theme and WooCommerce plugin and you are getting notice about the files being outdated, please do not worry. WooCommerce authors updated the plugin very frequently, and therefore it is likely you will get the notice as on the times of the publication we included older version. This that not affect the the functionality. Next time we make update we will provide newer version.