Information is entered into an Excel worksheet by modifying the cells within that sheet. The process is pretty much the same regardless of whether you are entering information into empty cells or cells that already contain data. To enter information into an empty cell, simply activate the cell and then begin typing. As soon as you do, the formula bar becomes activated and two icons appeared to the left of the formula bar.

Once you finish typing you can do one of two things: you can either cancel, to abandon the changes you've made to the cell; or enter, to confirm the changes you've made. To cancel, either click on the cancel button on the left of the formula bar or press the escape key on your keyboard. Alternatively, you can confirm your changes: to do this you can either click on the Enter button to the left of the formula bar or press the Enter key on your keyboard.

The action of pressing the Enter key does two things: it confirms your data entry and, also, moves you down one cell. This is usually pretty convenient. However Excel allows you to decide what happens when you press the Enter key. To specify this, click on the Office button and choose Excel options. On the left of the dialog box, click on the advanced button. This will display "Editing Options". The first Editing Option reads "After pressing enter move selection" and allows you to choose the direction in which you move whenever you press the Enter key.

As well as choosing "down", "right", "up" or "left", you also have the option of completely deactivating the movement. This means that, whenever you make an entry and press the Enter key, the information is entered into the cell but the cell remains active: you don't move down.

If you want to enter data into several cells, Excel allows you to highlight a range of cells and then to navigate between the highlighted cells, entering information as you move. For example, if you are filling out an invoice, you can select a matrix of cells under the "quantity", "description" and "unit price" columns. After you've entered the quantity, you can then press the Tab key on the keyboard to move to the "description" column. You then press Tab again to move the "price" column, and so on.

When we reach the last column of our selection, pressing Tab again moves us to the second selected row. When we reach the bottom right of the selection, if we continue to press Tab, we are taken back to the top left once more. Excel even allows us to move in reverse by pressing Shift and Tab keys together.

As an alternative to moving right and then down, you can move down first and then to the right. To do this, press the Enter key instead of the Tab key. Pressing Shift and Enter allows you to move in reverse: up and then to the left.

There are two ways of entering information into cells that already contain information. The first is simply to activate the cell, type a new value and then press the Enter key. The second is to modify the current value of the cell. To do this, you can either double-click on the cell and edit the cell directly; or you can highlight the cell and then make your changes in the formula bar.