Admin users can edit who can view and/or post Activities (Instructors and/or Customers). Follow these steps.
Step 1 - Activities Page
Head to the Activities page (My Company > Activities tab).
Step 2 - Edit Settings
Click the cog icon to open the settings beside the Activity you want to edit. You can edit who can view and/or post the Activity under "Visibility."
Step 2b - Internal Activities
For an internal Activity for Admins only, leave all boxes unchecked. For an internal Activity that includes Instructors, check whether they can only view or post the Activity.