When you have a series of emails, Outlook will seperate the emails into a series of pages. This option lets you jump to the page number you would like to go.

Click the first icon on the far right to jump back to the first page of emails.

Click the second icon on the far right to go back to a previous page of emails.

Click the third icon on the far right to go to the next page of emails.

Click the fourth icon on the far right to jump to the last page of emails.