The currently-selected texture is rendered in full at the top-left. Drag the A, B, and C handles to set the uv coordinates for the corresponding vertices of the main triangle. Drag the A, B, and C dots of the main triangle to change its render location. Click the buttons at the bottom to set the texture. You can also supply a custom texture of your own - to do this, click on the "?" button for directions, then click on the "Custom Texture" button to view it. Link to the tool for converting images to use in this project: http://www.tiberiumfusion.com/external/scratch/texturemapping/