To create or edit shapes, you need to open the 'Settings' window and select the 'Puzzle Shape" tab.
It is very easy to create shape sets and shapes. To create a shape set, click 'New' in the 'Shape Sets' group box. You will see that you can also 'Rename' or 'Delete' the selected set as well. Please note that if you delete a set, you will delete all of the shapes associated with that set.
You will find similar controls in the 'Shapes' group. You can 'Edit', 'Delete', 'Duplicate', 'Copy' or 'Rename' a shape as well as create a new shape by pressing the corresponding button. You will also find that you can 'Move' a shape by holding down the command key (the 'Copy' button will become 'Move').
In order to 'Edit' a shape, select the shape that you would like to 'Edit' from the popup menu and then press the 'Edit' button. A window similar to the one below will appear. You can adjust the shape's width and height by changing the value in the corresponding text field (please note that this will not scale the shape, it will only increase or decrease the area for the shape). To toggle a square on or off, just click on it. To draw, just hold your mouse button down as you move across the grid. If the first square you clicked on was off, all squares you move across will turn on (or stay on if they were already on). The opposite is true if the first square was on.
In the top left corner of the window are two buttons. One to rotate the shape 90º clockwise and the other to flip the shape horizontally. If you press and hold the alt/command button down when the mouse is over the button, it will change the effect. For the rotate button, it will now rotate the shape counter clockwise and for the flip button, it will now flip the shape vertically.
When working with your shape, you can press the 'space bar' to allow you to adjust the current shape's position in the grid. (NOTE: any part of the shape off the screen when you release the mouse button will be lost). You can also press the alt/command button while working with your shape to fill an area.
If you make a mistake while working with your shape, you can use the undo button to back up as many steps as you like. You can also reapply a step (assuming you haven't started drawing to the shape).
Press the 'Done' button to save your changes or press the 'Cancel' button to revert to the original shape.