To use Helmut, you place your film on a surface that illuminates the film evenly from below (e.g. a phone/laptop/tablet/computer screen, a window with the sky in the background, a professional or DIY lightbox). You should be able to get results as long as the film is illuminated evenly. Next, you launch the Helmut app, frame the film inside the camera, and snap a shot.
Via PetaPixel (thx Adrian)