Change the names of the text boxes and the command button to more meaningful names.
Click the top text box on the form.
Select Textbox1 and type txtRadius in the (Name) row in the Properties window.
Click outside the row for the change to take effect.
Repeat steps 1 through 3 for the other text box and name it txtDepth.
Repeat steps 1 through 3 for the command button and name it bOK.