how to create the mini map showing the player current position inside the game as red dot.
when ever player moves inside the terrain the red dot inside the mini map position should change according to the player position .
how to create the mini map with red dot inside the top
you can use 2nd camera as minimap,basically create a 2nd camera and set it to display depth only with orthographic option below it, and set rotation to 90 degree to show it as top view
you can check this thread , i think it is exactly what u want, except the view settings(which u can set as u need)
http://forum.unity3d.com/threads/72656-A-subwindow-for-the-second-camera-view
for the red dot to follow the player, my way is to do that is to create sphere object with lowest height, change material color to red and locate it up to your player and just below the 2nd camera and finally attach that game object to your player in your hierarchy to move with your player
make sure you locate your 2nd camera above your player as well to display the player.
hope this helps