To do this, click on frame 12 to select it; then right-click and select "Copy Frames". Next, click on the next frame--frame 13--and right click, before selecting "Paste Frames". This will place a copy of the keyframe on frame 12 on frame 13.
Now, to get the blue circle ready to be shape tweened, we'll have to convert the instance of it on frame 13 it from a symbol back into a shape.
