Selecting Levels
Use the drop down lists on the top to select level file and a level in that file. Another way to select a new level is by clicking the arrows next to the level selector or by pressing the Page Up and Page Down buttons on the keyboard, this will select the next or previous level. In the Options dialog you can specify which files and which levels are selected and if they are selected sequentially or randomly.

The icons in the file selector are:
   Selected File
   File with all solved
   Selected file with all solved
   Own Level file

   A star in the Level Selector indicates a solved level.

Saving and Loading
The state of the game in a tab can be saved to a file by selecting "File" - "Save Game as" in the menu. You can then later return to this point in the game by clicking "File" - "Load Game".

Skins
Change the look of the game by selecting skin. There are several skins to choose from. Click the Skin Selector in the toolbar to select a skin. Next to the Skin selector there is a control for adjusting the skin size. There is also a Skin dialog under "Options" - "Select Skin".

The menu "Options" - "Options" brings up a dialog, under the "View" tab are several options for automatic skin and window adjustments.