Changing the Sharing Permissions on Your Outlook Calendar
1. Open the Outlook Desktop App.
2. Click on the Calendar icon on the left side bar.
3. Click Share Calendar in the top navigation menu and then when the drop-down menu appears, click Calendar under your email address.
Everyone who you have not set custom settings for should be set to Can view when I'm busy. You can change this by selecting the desired permission at the bottom of that screen and then clicking Apply.
4. To customize permissions for a specific person, click Add to set up the permissions for that person.
5. Scroll until you see the name of the person you want to add or use the search field to search for the person. Click on their name to select them and then click Add.
6. Select the permission you want to assign to that person and then click Apply.
7. Complete steps 4 and 5 for each person you need to change permissions for and then click 'OK'.