Conditional tkinter button

I would like to make sure that the file button here is being clicked in the first place before others button is being clicked.

def open_file():
    tf = filedialog.askopenfilename(
        initialdir="C:\\Users\\ASUS\PycharmProjects\pythonProject",
        title="Open Text file",
        filetypes=(("Text Files", "*.txt"),)
        )
    pathh.insert(END, tf)
    tf = open(tf)  # or tf = open(tf, 'r')
    data = tf.read()
    file.insert(END, data)
    tf.close()

filebut = Button(root, text="Select File", justify='center', command=open_file, height=2, width=30, fg='black')
filebut.place(x=30, y=80)#240

So, whenever I choose a file, the path will be displayed here.

pathh = Entry(root, width=45)
pathh.place(x=30, y=140)

However, I would like to add something to the buttons below to prevent user from clicking it as they are required to choose a file in the first place before clicking the buttons below. Nonetheless, if they tend to press the button below before selecting a file, it should pop out an error message.

mostActiveAuthor = Button(root, text=" MOST ACTIVE AUTHOR", height=2, width=38, command=ACTIVE_AUTHOR, fg='blue')
mostActiveAuthor.place(x=30, y=180)

mostActiveDay = Button(root, text="    MOST ACTIVE DAY", height=2, width=38, command=ACTIVE_DAY, fg='red')
mostActiveDay.place(x=30, y=230)

timeHighlyActive = Button(root, text=" TIME HIGHLY ACTIVE", height=2, width=38, command=HIGHLY_ACT, fg='black')#35
timeHighlyActive.place(x=30, y=280)

maxNumOfWords = Button(root, text="MAX NUMBER OF WORDS", height=2, width=38, command=MAX_NUM, fg='brown')
maxNumOfWords.place(x=30, y=330)