Gui -> Dateime -> grid

[Larz60+]

you can't print into a label (line 33), you must assign text line in line 31
change line 33 from:

label_2 = Label(mainWindow, print(today.strftime('%m/%d/%Y')))

to:

label_2date = today.strftime('%m/%d/%Y')
label_2 = Label(mainWindow, text=label2date)

this only works once, because the second time, you can't create another label2, you need to reuse existing one
to do that you need a tkinter StringVal, set to the date, and in the label use textvariable = StringVal name.