If you are wanting to map multiple locations you should be using a recordset for this. This means that you will first need to have the locations specified in a table in your db. Once you do this you can just add a recordset to your page by going to Server Behaviors > Recordset.
When you have it on the page you can check the show multiple checkbox and select the recordset from the select list.
You can edit the info window by choosing custom from within the interface, when you choose custom you can alter any of the html that is used in the info window and what it says. I'm including a screen shot of this for your reference.
We have a bit of info about using the tool and accomplishing specific tasks on the products support page, here is a link:
pro-maps-for-google/
Let us know if you have any further questions after checking on the documentation for this.
