1.How should I store packed sheets?

Store in a protected, shaded, ventilated site, with no direct exposure to sunlight and winds.
In outdoor temporary storage cover with opaque protective film, and avoid PVC films and heat-absorbing materials.
Please note: Surface protective films that cover sheets are highly sensitive to heat and direct sunlight. Excessive heat and direct sunlight before taking off the film can cause gluing of that film to the sheet surface, after which it will not be practically possible to remove it from the sheet!