Hmmm… i tried to get both in one screenshot. Remember that iam creating a tile based game, so that my comments are related to that!
First, iam breaking through every element of the array (“Get through the GridArray incrementally”).
After that, i recreate each element, beginning with the tinyiest (“Recreate Y-Axis”).
Every recreated element will get stored in an temporary array (eg. “Temp2D-y-axis”).
These Temp. Data is the basis for the elements of the next step (eg. “Recrete x-axis”).
Just repeate the steps, till the last stage, where alle the temp arrays get the content of the original array (“recreate floors”).
With those steps, i have broken down through the whole array and did recreated it completely WITHOUT altering any element, but this will be next:
The upper comment box (“Check if actual tile is the searched one”) will look for the element, what will be altered.
If the position is reached, the normal recreation process will be ignored for this step and an alternative one is used (“alter tile with fiven information”).
Glad i can help 
Something got cut up:
At Input: “NEW Tile Definition”
And on the right side; the “set array elem” is the last used function (Compare with “recreate floors” eg). There is nothing more.
PS: The images are in FullHD Scale. So either download them or open them in a new window, to watch them at full size
