Code

// Load the workbook from a file
Workbook workbook = new Workbook();
ExcelImporter importer = new ExcelImporter();
importer.Import(@"c:\Users\Meppy\Hearthstone.xlsx", workbook);

// Obtain the first worksheet
var worksheet = workbook.Worksheets[0];

// Iterate over the worksheet cells and collect the max row and column
int column = worksheet.Cells.Max(cell => cell.Column) + 1;
int row = worksheet.Cells.Max(cell => cell.Row) + 1;

// Display the result
Debug.WriteLine("columns: {0}, rows: {1}", column, row);