Vaude Swing Carrier sun canopy; how does it work?

[Nojomamanbooby]

Hopefully someone with a Vaude carrier can advise - We've recently bought a second hand Vaude Swing, it came with what I assume is a sun canopy / raincover in the pocket ( yellow with a window, looks like the mask of a radiation suit!) it's just floppy material, no tubes or wires in it -and there doesn't seem to be anything on the carrier that can make a sun canopy ; are we missing a part ? We noted that if you open the Velcro on the back of the carrier at the bottom, there is some tubing with some foam on the top that pulls out? Weren't sure if this was meant to come out to form the canopy, or it's part of the structure of the carrier? (Hopefully that makes sense to someone) TIA