1. Open Outlook
2. Go to File – Open – Import.
3. Select Import from another program or file and click on Next.
4. Select Outlook Data File (.pst) and then click on Next.
5. Click on Browse.
6. Select the desired .pst backup file and then click on Open.
7. Click on Next.
8. Click on Finish.
9. A window containing a progress bar will appear. When it closes, the files will be imported in the mailbox.