1.First you need to download Drupal Location and Drupal GMap modules.
2.Browse to admin/build/modules, and enable Gmap Location, Location, and Gmap
3.Browse to admin/settings/location, check ‘Use Google Map’ and enable ‘Display of Locations’
4.Get an API key for your URL by going to http://code.google.com/apis/maps/signup.html
5.Go to admin/settings/gmap, put your API key, and save the configuration.
6.Browse to admin/settings/gmap_location and enter t the settings of your node maps and user.
7.From admin/user/permissions set permissions for the location modules and gmap_location.
8.From admin/content/types, edit content types that you want to display location information, and then turn on ‘ Locative Information’ settings.
9.create a new node for a type that you wish to set location. Under Location, select the map which will add a marker. Then pick and drop the marker repetitively to zoom in .
10.From admin/build/block, set Location map block in Content region.