Okay. I'll walk you through it.
Open the screen editor. Operator --> Edit Screen
Then look at the attached pictures.
1. Be sure that you highlight the screen name at the top of the "screen tree manager".
2. Select the 2nd tab of the "Properties".
3. Open the PLC Script.
Put the code at the end of the PLC Script, just above the Last Line stuff from Mach4. As good practice. Put the Date and your initials by your new code to keep track of what you added. Exp. CB 3-7-18