By default, any employee who signs in to your company account will be able to view a limited profile for each of their coworkers, either via the org chart, the directory, or the calendar. To restrict the scope of who employees can see within your organization, and to control who they see on the calendar, click on Settings > Permissions. On this page you'll see a box called "View Permissions" which will show you what your current settings are.
Click the Edit link to make a change to your settings. In the window that appears, choose the appropriate view permissions that you'd like your team to have.
These options are explained below:
Everyone: As you'd guess, this option lets employees see everyone else within your organization, both on the org chart, in the directory, and on the calendar.
Department: This option restricts access to view only those people who are in the same department.
All Subordinates: This option restricts access to view only those who are subordinates.
Direct Reports: This option restricts access to view only those who are direct reports.
Only Themselves: This option restricts access to only their own profile. Neither the org chart nor directory appear at all when this option is selected. The calendar will only show events for the user.
If you do allow employees to see others within your organization, by choosing options 1-4 above, it's important to note that they can only see a very limited profile with name, title, photo, and basic contact information. No sensitive or personal information will be shown.