If an event spans multiple days, you need to create a calendar event for each day. This is made easier with the duplicate event tool.
1. Create the first calendar event, then go back to the calendar list.
2. On the calendar list locate the event you just created and click on the duplicate tool. This will open a new calendar event with most fields populated with information from the event you just created. Simply change the date and any other information that differs.
3 Click on the Save button.
Repeat step 2 and 3 for each event you want to duplicate.