Finally, in that row, you need three columns. Don't forget to end your columns with the </td> tag.
<td>Row 1 Column 1</td>
<td>Row 1 Column 2</td>
<td>Row 1 Column 3</td>
You should also end your rows with the </tr> tag. Some browsers don't need it, but you want your page to be compatible with the most people, right?
</tr>
Then you have your first row!. Repeat it twice more for your 3 x 3 table:
<tr>
<td>Row 2 Column 1</td>
<td>Row 2 Column 2</td>
<td>Row 2 Column 3</td>
</tr>
<tr>
<td>Row 3 Column 1</td>
<td>Row 3 Column 2</td>
<td>Row 3 Column 3</td>
</tr>
Finally, you should always remember to end your tables. Again, some browsers don't require it, but other browsers will show a blank page without the final </table> which can be very disheartening after all the work you've done to create the table.
</table>
