This guide will enable you to:
1) Restore a backed-up archive of an email account to Outlook on your Windows computer.
Check:
1) You have backed up your account already. Ensure you took a backup of all of the folders from which you require data (typically the root folder, so the backup contains data from your entire account).
Add the account:
1) Open Outlook.
2) Select File > Info > Account Settings > Account Settings. This shows all of the accounts listed in Outlook.

3) Click the "Data" tab, then click the "Add" button.
4) Select the backup file from the location in which you saved it, then click "OK".

5) Your backup will be shown alongside any email accounts in the pop-up window, and above or below the folder structure of any email accounts in the left navigation pane of Outlook.

6) Your backup provides a copy of all of the data you saved. Be sure to also copy and save the backup file somewhere safe.
Copying data from a backup file to your active account
7) Your backup file only stores data on your computer. If you wish, you can copy data to an active email account.
8) To to this, open the relevant folder (e.g. Inbox) of your backup file, select the messages you require, then copy them to an appropriate location in your active account (e.g. the Inbox of the account above or below your backup file).