When you designate your calendar, you are allowing someone else to have rights to view and/or add items to your calendar. The other person is called the Designee. To access the designate feature, go to Tools > Access Rights. There are four areas you need to consider:

Designate tab - Allows you to add the designee to your calendar. You need to first add the individual to your list by typing in their name and clicking on the green check mark button to add. With their name highlighted, check off the appropriate rights you would like them to have on the following tabs.  If you want to allow everything, simply check off "Full Designate" and you are done.

Viewing tab - You need to decide whether to allow the individual(s) to view entries or times only for any of your meetings, events or notes.

Viewing Tasks tab -  You need to decide whether to allow the individual(s) to view any of your tasks.

Scheduling tab - Allows you to enable someone else to schedule you tentatively for a meeting.