To change dates on the three displays, open the .psd, select wanted date, and correct color for what display you want the date to be on.

After this, save it as a .tga(and convert to .vtf) or save it as a .vtf straight away. Now, if you are making a date for example for the destination display, you save it as "destinationdate.vtf" and place it into the correct place (materials\models\Nirrti\BTTF\DeLorean\), and replace the current "destinationdate.vtf" with it.