In the first line "Num_nan=find(isnan(Table));" you get the positions of the NaN, but this is just a number. For example, applying this on the following matrix:
Num_nan = 5
But then you should use this number to get the row and column and this is done with the other lines.
There are 3 numbers in one column, so
So the column number is 2,
for the row we use the remaining of 5/3 which is 2
so NaN is at (2,2).