First, I thought that I don't need to use a string, because I thought that it usually applies to text not numbers.
As for the matrix, I don't know how to describe it, but the matrix is the area that we choose to work with in the worksheet. Within the chosen area, we assign a number of marked cells that are supposed to move in the selected area. And right now, I'm working on the userform where I'm supposed to enter the size of the matrix.
Anyways, thanks for help.