I have the 24mm spindle version.
There weren't any instructions in the box. I fitted the cranks and tightened the locking bolt to 20nm. When tightened the cranks don't seem to spin that freely., They spin OK but just less so as I tighten the locking bolt. If I don't tighten the locking bolt this way then the cranks work loose.
I'm assuming everything is okay, I just feel I've missed something due to how they don't spin super freely when tightened.
Otherwise great cranks, useful to be able to test different cranks lengths.