The left arrow button builds all of the resources from the Capture panel to the Resource List.
The trash can button clears all of the resources from the Resource List.
The right button applies the resources from the Resource List to a layer in your image editing application (Photoshop or Fireworks).
For more detailed information, consult the Tutorial pdf included with your IconBuilder download.
We've tried to anticipate most questions you might have. However, if you can't find the answer you're looking for here, send us your query and we'll answer it personally.