In Photoshop, File > Import > Video Frames to Layers and select the downloaded video. DON'T IMPORT THE ENTIRE CLIP! Adjust the sliders so it only imports the very beginning of the video, before the camera pulls back.
Change to video timeline format, not frame (click icon in bottom left of timeline panel). Choose a frame to be the “still” part of your image.
Make a new layer above all the other layers, and click on it (just a single click, to make sure you're on that layer).
Use the stamp visible command: Shift+Ctrl+Alt+E on PC, or Shift+Cmd+Option+E on Mac. This will create a still image running the entire duration of your timeline, called a master frame.
Add a Layer Mask to the master frame, and paint a black mask to show the area you want movement in (white shows through, black covers up -- so you're covering up the "still" part of the image to reveal motion). Mask out just part of the stream, and leave the rest still.
Make all layers visible and play the clip to make sure your action is visible in full without anything being hidden. Make any adjustments to the mask if you need to.
Save your edited PSD file, and save as a GIF. Submit the GIF to this assignment.
Can't change a rubric once you've started using it.