Hello Priyanshi,
1. The easiest way.
If your service that populates the Google Map returns also the additional attributes that should be shown when marker is selected, you can bind the SelectedRows of your service with the grid - this way, when you select the marker, a whole data regarding selected record will be passed to the grid:

2. The more flexible way.
If you don't have the data as an result of the same service or don't want to use the previous way, you can pass the selected location parameter to additional service that returns more data:

Hope that clarifies a little bit. In case of any questions, don't hesitate to ask.
Regards,
J.