What does it mean: the theme is not compatible with WooCommerce?

Question

WordPress

Installed this plugin, during the initial setup it shows a warning that the theme is not compatible with the plugin. What does this mean, experts!? This is a plugin, that is, an extension of functionality. From the point of view of what then it is not compatible? From a layout point of view, right? I am making the first site, and fussed at this point, so I apologize for amateurism. How do you pull on your sites not on ready-made themes this plugin?

Answer 1

Support must be declared in the topic

add_action( 'after_setup_theme', function() {
  add_theme_support( 'woocommerce' );
} );

Answer 2

That means, change the theme
PS
The official Woocommerce theme (that is, fully compatible) is Storefront