1. To set-up an automatic email to notify owners of a review having been received, you need first to set up a review notification email template.
See this help centre article for information how to create an email template.

You can use tags to auto-populate booking specific information, e.g. the property name, using tags, if required.
For more information re using tags to create email template, see this help centre article.

2. You should then go to Emails/Letters > Automated Emails, and add you review notification template to a letter group.

3. Next, select Show letters in the Select action drop-down to the right of the letter group, click Go.

4. Tick Edit.

5. Edit the letter and set the criteria for the auto email as shown in the screenshot below.

6. Make sure to tick the box at the bottom next to 'Owner' in order to send it to the owner only.
Scroll to the bottom of the page and click Update letter in the bottom right hand corner.

7. When you have done this, son the Automated Emails/SMS page again, click the add to existing bookings button in the top right.
For more information about this feature, see this help centre article.