2d pointer as a data member of class

i have to write a code for matrix addition using a oop. I made a 2d pointer as a data member of my class. I initialized my pointer in the default and parameterized constructor. When i am trying to access the elements to which my 2d pointer is pointing i get error.

void Add(int const &a)
{
    for(int x=0;x<row;x++)
    {
        for(int y=0;y<col;y++)
        {
            (*(*p+row)+col)=(*(*p+row)+col)+(a.(*(*p+row)+col));
        }
    }
}

int **p is my 2d pointer data member here. I am new to classes any help would be appreciated.