The service manual is a little bit like the laconic "remove engine
and transmission" stage in some car shop manuals... not too helpful
unless you've seen it done before.
Been a while, but I think I
started at the bottom where you can more easily spread the side of the
fret a little. Then, slide an old credit card or something similar
between the fret and the tube, move it upwards and when it starts to get
stuck, push the fret back and you should hear a "click" when another
clip lets go. Repeat on both sides until you reach the top.
Then you can move it a bit upwards and remove it.
I believe you should stretch a side wide open and pull it off instead
of sliding it all the way up over the top (which destroys some foam
spacers), another thing the service manual doesn't reveal...