You can access the Linked Configuration window by holding the ALT key during launch.

I recommend turning this effect off. If it's on, then the puzzle will shake every time you clear a string of squares, which can slow you down.

Main Menu > Settings > Block Clear Effect.

The object of the game is to clear all white squares in the puzzle. However, you can only clear the squares by creating strings of them, which are listed on the left side of the screen.

To create a string, press and hold RMB on the starting square. Drag your cursor either horizontally or vertically, connecting the white squares. When you let go of RMB, your string will disappear.

Each of the images in the following sections have certain squares connected for you. Some levels require multiple steps in a certain order, which are listed in this guide.