You can see additional tips and downloads in the gray boxes within the workflow.
To install the missing nodes, go to "manager - Install missing custom nodes".
All you need to do is load the images into "Load Black", "Load White", "Load Red" and "Load Green". In "Mask Frames" you can see the approximate movements of the images. This makes it easier to control the final animation. "Load Black" can serve as a basis, transition, or background, depending on your idea and the selected mask.
