You can follow these general instructions:
- Go to Google Maps and find the business with the review you want to flag.
- Click on the number of reviews.
- Find the review you want to flag.
- Click on the three dots in the top right corner of the review.
- Click on "Flag as inappropriate".
- Follow the prompts to provide Google with a reason why you believe the review should be flagged.
Google will then review the flagged review and determine if it violates their policies.