On the right hand side, there is a dropdown menu “Who can view this site?”
You may opt to let only members or those who have logged in (shared their information with your site) have full privileges to the site and its contents.
You may also select this setting on other pages of your site. For instance, under the calendar page, on the right hand side, there is a similar option, so that only members/anyone/those who have logged in can see the published events on your calendar.