Open Outlook
Go to the Calendar view
Select Add Calendar
Choose From Address Book or Open Shared Calendar
Search for the person’s name
Select the calendar
Click OK or Add
If prompted, request permission from the calendar owner
If you already have access, the calendar will open in your calendar list
To view it, check the box next to their calendar name
If you need access, ask the person to share their calendar with you in Outlook or grant you permission through Microsoft 365/Exchange