A turning mixes the hot core with the cool edges, lets fresh air in, and re-wets what has dried. The DMR long method schedule gives turnings on days 6, 10, 13, 16, 19, 22 and 25, with filling on day 28, and gypsum going in at the third turning. The Hindi farmer folder prints an eight turning version of the same ladder.
Both DMR documents also call for an insecticide at the last turning, and they differ from each other by a factor of ten on strength. Copy neither. Check what is approved for this use today and follow that label.