Set and Level Four Corners of Blocking
Set the four corners for the deck. Digging about 6 inches into the ground, create holes for the blocks so you can adjust (raise or lower) to make them even. The blocks should be spaced to make a 7' x 19' rectangle, leaving about 6 inches from each block for deck boards to add another 8' x 20' rectangle. Using a string level or laser level, make sure each block is level. Or, check if corner blocks are level by running a straight board through the divots in corner blocks and checking with a level.