To select a cell in a Word table, hover your mouse to the left side of the cell that you want to select. You will see your mouse pointer turn into a small black arrow. When you see the arrow, click your left mouse button and the cell will be selected. You will know that the cell is selected when it is highlighted in black.
To select multiple cells that are next to each other (contiguous cells), select one cell as noted above and then drag left, right, up or down with your mouse to select more cells. Alternatively, you can select one cell, then hold down the SHIFT key and use your up, down, left and right arrow keys on your keyboard to select additional cells.
To select multiple cells that are NOT next to each other (non-contiguous cells), select one cell, then hold down the CTRL key while selecting more cells with your mouse.