The first window you see when you start the program:
The ui should be pretty straight forward. On the top of the screen there is the menubar. Then there is two toolbars, one with a forward and backward button, and one with a button for each exercise. Key bindings:
Back: Shift-Ctrl-Left
Forward: Shift-Ctrl-Right
Reload: Shift-Ctrl-Up
Below that there is the main view of the window where the welcome screen is viewer, and where the exercises will be.
The status bar on the bottom is only visible when viewing html files.
To get help on a specific exercise, start the exercise by clicking on the exercise toolbar or select an exercise from the file menu, then press F1. The help will be showed in the main view of the window. To get back to the exercise, press the backward button on the top-left of the window or use the key bindings described above.
For some exercises you will notice links in the help text that bring you back to the exercise, like clicking on this link will start the chord exercise. These links can also configure the exercise, so help texts can be written for exercises with several links starting with the easiest configuration and then making them more and more difficult.