Nx Journaling Custom Command Project

Hello,
I am trying to make a custom command button for nx by using nx journal vb scripts. The algorithm is like this;

1)User will choose the areas.
2)The areas will be divided to a constant.
3)If the result is bigger than an other constant, a string message will come to screen. Else an other string message will come to screen.

The problem is the vb code of this algorithm. And the user interface of this command. Can you help me with these problems?

Thank you.