The Now tab shows you what is happening online in school in real-time.
The first section is an overview of aggregated data showing you how many students are on which websites at the same moment you are viewing your Teacher Dashboard.
The icon for each website should allow you to complete a quick check and notice who is accessing a site they are not supposed to.
The Student list below the top section, displays all students that fall into the group you've selected using your Hierarchy Header. Each individual student can be selected from this window using the > which takes you to another page to apply an action/setting for this individual student.
To apply a setting to all students, simply click the > and check the box marked Select All.