Transmission brake dust cover fitting

I can’t work out how to fit this. Do I just push it down as far as I can along the operating rod and hope that it stays in the right place, or does something hold it in place? The picture in the (Series II !!, maybe i should look in Series III...) workshop manual kind of implies that it pushes through from the other side of the back plate, but i am not sure that is possible?
Can’t find a Youtube video on this, and my photos don’t show this either.

I think you pull and stretch it over item L clips

The cover (and the overlapping clips 'L') are outside the brake plate, and as Steve says, stretch it.

The clips are U shaped [L on diagram above] that hold the expander in place but allow it to move some, cover stretch's over clips.

thank you all for your help - that did the trick (although on a separate but related note, when i tried to put the new curvy spring back on the brake expander, it pinged off and disappeared into another world, never to be seen again - just as well as i had the old one).