Keep bags off the ground on pallets or planks, at least 150 mm up and 300 mm away from walls. Moisture climbs through floors and seeps through block work.
Stack no more than ten bags high and keep the rows tight, so less air moves between them. Cover the stack with a tarpaulin in the wet season.
Use the oldest bags first. A simple chalk date on each delivery is enough. Anything past 90 days should be tested before it goes into structural work.