Try using set back. It is the easiest (IMHO)
Cut a small piece of the same material, say 60mm long.
Bend through the middle, and measure each leg.
The total will be over 60mm, the excess material being what was gained in the bend.
That extra amount is the set back.
Now after marking the first section, move back by the setback and start the next panel from that line, and so on.
The bend line for the blade is central between the lines, but with a folder, it won't be evenly between them.
Do a few test bends first, and it must be with the same material you will use.