You can add characters to your drawing to create different formations.
The list of characters are divided into two groups, shapes and letters.
To insert a shape, it's very simple: Just click on one of the buttons and then click where you'd like it to go. Then make sure you unselect the button once you're done inserting that particular object into the picture.
If you'd like to move an object around, click on the cursor symbol all the way on the left and on the top row, then click (or highlight) the object or group of objects. You can then use the mouse to move it to where you want to go.
For more precise movements, you can also select and/or highlight the object(s) and move them around with the arrow keys.