If you want someone else to go to file > open > other user’s folder and be able to open your second calendar that way, it won’t work. Only the main default folders of outlook can be viewed that way. Instead you must first grant permissions to your mailbox at the top level. Right-click where it says Mailobx – yourname. Go into properties and grant read permissions at that level. Then grant permissions on the second calendar. The user will then need to add your mailbox to their folder list. Tools – account settings, view or change, more settings, advanced, add. This will add your mailbox to their folder list but they will only see the calendar you gave them permissions to see, not your full mailbox.