If it is these, they go on the outside
of the liner...between the liner/shell...in my pic the orange c's are covered with white tape so the don't rip off when I remove the liner from the shell after each day to dry both the shell and liner. The bigger thing is the butterfly, the upper things are the c's and below are the j's....the c's and j's go on each side of the liner, two per liner
You can use any or all in a combination, imho/imhe use the butterfly first then add the c and later the j if you need more...adding layer/build up will pinch the heel/ankle more. If you get the foam sheet, just cut out in the same as in the picture.