The homepage of your site can be provided by one of the apps installed in your Webasyst account. To choose an app to be responsible for providing the homepage, ensure that the rule with URL * (asterisk) in section Site → Structure is created just for that app.
Below is shown an example of the site structure where the homepage is provided by the Hub app:
Apps Photos, Blog, Hub, Shop-Script are capable of automatically generating a homepage, and there is no such functionality in the Site app. For this app, you have to create a homepage manually.
To do so, after you have created a rule with the URL * for Site app in "Structure" screen, proceed to "Pages" screen and create a new page with empty URL. This new page will be the homepage of your site.