Here's my recollection...
You start off with three nice new tubs
You put glue on the shiny new sprint rim..it goes tacky
You put the tub on and pump it up to 120psi
(you do this for both wheels)
You then fold the "spare" and secure it to the underside of the back of the saddle using a "used" toestrap and you carry a frame pump
Then one day you're out on a ride and the tyre explodes with the verocity of a shot gun
You have a flat
You swap it out for the new spare, the existing glue on the rim is still tacky so holds the tyre, you pump it up to 120psi
When you get home you unstick the tape of the inner side of the tyre, cut the stitch cord near the puncture and unstitch enough cord to easily expose the puntured area of the inner tube...fix puncture in the normal way then pump up and test, also check for other problems with the tyre
Restitch the canvas (errr don't stitch it to the inner tube though
) and stick the base tape back on as best you can
Pump it up again...
You now have a used spare tub with a lump in it
You go for a ride you get another puncture
Repeat as above except you make a better job of the stitching whist doing the repair and this then becomes your "proper spare" but you buy another new tyre too
You now have 4 tubs
Two unpunctured
One punctured and repaired not so well (the bad spare)
and one that is your good spare that does not have any lumps in the stitching that you then carry as described above
It is your choice or not to carry the bad spare
Hope this helps
Cheers
Mike