To Manage the Google Business Profiles for multiple locations, there is a simple 4 point rule.

1) Setup & Consistency

Create Individual Profiles: Create a separate profile for each location using the Google Business Profile creation tool with the Physical address matching the exact location.
One Single Google Account: Keep all the Profiles under one single google account for easier cross linking & management.
NAP Consistent Profiles: Make sure that the Name of your Business is Identical for all locations with corresponding Address & Phone numbers.
Website: Each Location should have a separate dedicated web page under your website which when linked to Google Business profile should act as a direct link or landing page.

2) Optimization

Optimize each GBP Page: While creating Google business profiles for different locations make sure to add the location specific data such as photos, address & contact details. Also add any specific category intended for that geographical location.
Tailor Made Content: Use the keywords that abide to the local requirements, so that users can connect using those keywords.

Positive & Location Specific reviews: Encourage customers to leave reviews on the specific profile for the location they visited by providing them the QR Code or Link for easy access & offer some discount coupons for motivation by adding posts on your GBP.
Reply to the reviews: Try replying to all the reviews both positives & negatives promptly. Offer the suitable solution for negative reviews.

Track Performance: Regularly keep the track of insights and metrics for each GBP for different locations separately to understand the gaps & try to address them periodically.
Create Standard Process: Schedule a task list for managing updates, posts, and reviews across all profiles in a timely manner.