Hi Abdullah,
I think it's better to put these questions in the "How Do I" forum in the future.
Anyway, you can use PositionToTileX and PositionToTileY - these functions take an x and y in the layout and they turn it into a number of a tile.
For example, if your tilemap is all over the layout and the size of every tile is 20X20, then the tile that is found in position 12,15 in the layout is called tile number 1,1.
Here is an example that uses it to make the tile disappear: