PrestaShop 1.6.x. How to display multiplе stores on Google Map

1. Go to Preferences -> Store Contacts section: 
2.  Add new store location by clicking the Add New Store button: 
3. Fill in the following options (the most important fields are Latitude and Longitude): 
4. Set the Status to Yes if you want to display the store.
5. Save the changes.

Hopefully, this tutorial was helpful for you.