The arrow indicates the direction of wheel rotation, or should point to the front of the bike. So long section to the rear.
Like with people and all animals, the toe is always in front, and heel in back. So when we say toe-in, it implies that the shoe touches first up front.
Current production KS shoes have the "plow" wedge in back, which also acts as a toe-in gauge, so if you install so the shoe touches front and back together that's correct. It may squeal for a while until the back corner wears off (happens pretty quickly) establishing the correct toe-in. If you want less squeal immediately you can put a piece of cardboard under the heel when installing to increase the toe-in slightly.
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