1 Create your first GUI application
2 Create a label widget
2.1 Set label font size
2.2 Setting window size
3 Adding a button widget
3.1 Change button foreground and background colors
3.2 Handle button click event
4 Get input using Entry class (Tkinter textbox)
4.1 Set focus to entry widget
4.2 Disable entry widget
5 Add a combobox widget
6 Add a Checkbutton widget (Tkinter checkbox)
6.1 Set check state of a Checkbutton
7 Add radio buttons widgets
7.1 Get radio button value (selected radio button)
8 Add a ScrolledText widget (Tkinter textarea)
8.1 Set scrolledtext content
8.2 Delete/Clear scrolledtext content
9 Create a MessageBox
9.1 Show warning and error messages
9.2 Show askquestion dialogs
10 Add a SpinBox (numbers widget)
10.1 Set default value for Spinbox
11 Add a Progressbar widget
11.1 Change Progressbar color
12 Add a filedialog (file & directory chooser)
12.1 Specify file types (filter file extensions)
13 Add a Menu bar
14 Add a Notebook widget (tab control)
14.1 Add widgets to Notebooks
15 Add spacing for widgets (padding)
Good old Tcl. Man, that language just absolutely refuses to die.
I remember learning in sometime in the 90's specifically to use Tk for some personal project or another. What a weird language. Pathologically dynamic where everything can be (re)defined at runtime, including control structures; "stringly" typed, so everything's a string; you can get at the variables in functions higher up the call stack, effectively "transforming the call stack into a call tree".
It's interesting to see that it's still alive and being used, and that TkInter is apparently "a thin object-oriented layer on top of Tcl/Tk.".