Create a Map in Unity

https://youtu.be/ZiZH07SQyAc, check this video and focus on the minimap on the right top corner..i want to make this exactly similar map fog of war effect where there will be fog visibility when the player open the map. The trailing open map will be become fog when player move to another place..the player only allow to view visible around the player only. The trailing map will become fog when it goes to another place..i only need the minimap and fog effect trailing similar like the video..i will use the code to implement to my game myself