1. Ensure that your mailbox is set up for "Server-Side Sync". To do this navigate to Settings > Email Configuration

2. Click on "Mailboxes"

3. Ensure that all email settings for the applicable user are correct as listed below

4. Navigate to the cog in the top right of the screen and select the option for "Apps for Dynamics 365"

5. Select the button labelled "Microsoft Dynamics 365 App for Outlook" and this will add the app to your exchange profile