1. Open Outlook and sign in with your Microsoft account.
2. Click on the "Calendar" button on the bottom left corner of the screen.
3. Right-click on the calendar you want to share, and select "Share" from the context menu.
4. In the share box, enter the email address of the person or group that you want to give access to.
5. Choose the level of access you want to give. "Can view when I am busy" or "Can view all details"
6. Click on "Send" button
7. The person or group will receive an email with a link to the shared calendar, along with instructions on how to access it.

Alternatively, you can share a link to the calendar that can be shared with anyone, even if they don't have a Microsoft account.

8. Go to the calendar tab in Outlook, click on "File" then "Share"
9. Click on "Create a link" button
10. Choose the level of access you want to give. "Can view when I am busy" or "Can view all details"
11. Click on "Create" button
12. You will get a link which can be shared with anyone you want to give access to.

It's important to be aware of the company's data security policies and comply with them when sharing a calendar on Outlook. It's also important to keep track of who has access to the shared calendar, and revoke access if necessary.