how to make a different column for blue and green in the given example?

Answer 1

I don't know if I understand what you mean, but if you want those to appear as normal columns, just remove the 'colspan' and add the absent td's:
<tr>
<td><br></td>
<td></td>
<td></td>
</tr>

Answer 2

Which example?

Answer 3

the one shown in the tutorial