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I can see where shims can be added and removed, at 2 points, on each upper control arm camber, or toe (ie. if you just put put a shim at one point and not the other).
You adjust caster by changing the shims on the upper a-arm. By putting more or less on the front or the rear you can move the upper ball joint forward or backwards to change the caster.
The toe is adjusted with the tie rods.
As Paul said, caster is changed by moving the shims from the front to back or vice versa. Camber is changed by adding or subtracting the same amout of shims front and back.