You can select a single cell by tapping on the cell. Similarly, you can select an entire row or column by tapping on the relevant row or column header, but to select a range of cells you must first select a cell to define one corner of the rectangular range of cells that you wish to select, by tapping on the appropriate cell. Then press and hold down on the cell that will define the opposite corner of the range. After one second the range will be selected, allowing you to perform any functions that involve a range of cells.
Another way to select a range is by double tapping and on the second tap, hold down and drag to define the range. Either method works well, but the first method is more convenient if you have a large range to select.
If you wish to select several rows or columns, select the first row or column (as appropriate) and then press and hold on the last row or column (as appropriate). After one second the range selection will be made.
