You can help by adding information on the use of this input method. Key combinations that are hard to figure out or even an image of the layout would be helpful. The information on this page will also be displayed from the help button next to the IME name on interface. List of all available input methods and more information about using them can be found on this page.
Letters Ш, Ђ, Ч, Ћ, Ж are missing in extension.