Stack on a clean cemented yard so leachate can be collected and returned. Stack size is set by climate, not by convenience. In the plains DMR recommends a stack about 100 to 120 cm wide and around the same height. In the hills, where outside air may sit between 7 and 20 degrees Celsius, the stack is widened to 130 to 150 cm with a height of about 150 cm so heat is not lost.
Keep the sides vertical and the top flat, press the edges lightly, leave the core loose, and never stack less than 300 kg.