Then click on the small box at the bottom lower right of the selected cell and drag vertically or horizontally to fill a range of cells. Notice that all the cells you select will be filled with the number. OR Select a cell, and enter a number. Then highlight the cell with the number and the cells to be filled. The upper leftmost cell has the address A1.
Columns are letters and rows are numbers.
Select cells A2 to A10. Ok, marginally interesting. Select cells A12 to A20. A dialog box comes up and you fill in the step value and the stop value. Put 2 into the step value and 20 into the stop value.