You can find a lot of those backgrounds and overlays here:
You would have to make the overlay move.
Go to the Writer Portal. Click into the script of your story. Press Preview on the part of the script where the overlay is being used. Go to Directing Helper (near the top right). Then click Overlay Helper (bottom right) and click on the overlay. You should be able to move it/shift it. Underneath it’ll give you a code. @overlay…shifts to…in…