Little Lathe works by rotating the shape you define at the left side of the window around its vertical axis and generating facets out of every rotation. The number of slices you use for the object defines the number of rotations.
To create the shape click on the left side of the window to add a new vertex or move an existing vertex. To delete a vertex press the Shift key and click on the vertex to delete. To add a new vertex between two existing vertices, press the Alt key and click on the first vertex.
The properties at the right side of the screen specify how the object will be created and rendered. The properties are self-explanatory, except perhaps the Sharpness Threshold which you can use to adjust at which angle the program will create sharp cuts instead of smooth cuts (this property only applies when the Smooth style is used).
Use the WASD keys to move the camera around. The numbers 2, 8, 4 and 6 on the numpad will pan the camera. The numbers 1, 3, 7 and 9 on the numpad will switch to predefined directions. The number 5 on the numpad will toggle perspective and orthographic camera.
With the mouse keeping the middle button down and moving the mouse will pan the camera. Keeping the right button down and moving the camera will rotate the camera.