Now that you have your background image in place, you can modify the text colours to better display over your background.
The sample login form has all text fields set to black.
Select any field and open the field attributes form.
Click on the Size/Colors tab and set the Foreground color for the field.
Note 1: You can ignore the background colour field as all of the fields are set to have a transparent background so as to let the background image show through.
Note 2: Don't forget to change the colour of the three fields that currently have no text being displayed.
Here is an example of a completed form with modified text and button colours.
Here is another example where the "Login As: fields have been removed as well as the Save button