Next fold the outer edge to the center, crease and open. Do the same for the lid. At the corner of the bottom of the lid fold a diagonal crease that bisects the small square created by the previous folds.
Unfold the 2 opposite sides. Refold the remaining 2 sides of the square along the crease so they stand upright and form 2 walls of the box. Fold up the third side, tucking the diagonal corner folds inward against it; wrap the third side over the folds: lay it in place. Repeat for the fourth side. Glue the points together at the center.
For more in depth instructions, please refer to this link.