Step 1:
You need 15 papers of about 15x15 centimeters for 3 boxes.
The papers for the large box are made by glueing 3 papers together. Prefold in half over the purple line.

Step 6:
Valley-fold these prefolded lines into the right direction

Step 5:
Fold to the centerline again.
Then unfold the folds of steps 2 to 5

Step 2:
Fold over this line, about 2 cm off the edge

Step 4:
Fold the edges to the centerline

Step 3:
Prefold in half over this purple line (fold to the centerline)

Step 10:
Fold this spot downwards

Step 8:
Glue both ends together

Step 9:
Fold this spot downwards

Step 7:
Fold over this line, about 1 cm off the edge

Step 16:
Repeat steps 3 to 6

Step 15:
Fold over the purple line, about 1 cm off the edge.

Step 12:
This is how the bottom of the box looks

Step 11:
Fold the other 6 spots downwards.

Step 14:
The lid paper of the large box is also made by glueing 3 squares together.
Prefold in half

Step 13:
Done.....

Step 21:
The large box is finished.... 

Step 19:
Fold the eight spots / corners downwards, the same way as for the box.

Step 20:
And the lid is done too.

Step 18:
Glue both ends together.

Step 17:
Fold the part below the centerline (see arrows) in half two times.

Step 22:
The papers for the medium size box are made by glueing 2,5 papers together. Prefold in half over the purple line.

Step 28:
Fold all eight spots / corners downwards

Step 25:
Repeat steps 3 to 6

Step 26:
Fold over the purple line, about 2,5 cm off the edge

Step 24:
Fold over the purple line, about 2 cm off the edge.

Step 23:
Prefold the edge to the centerline. Then prefold this folding line to the centerline.

Step 29:
Done.....

Step 27:
Glue both ends together

Step 30:
This paper is also made by glueing 2,5 squares together.
Prefold in half over the purple line.
Prefold the upper edge to the centerline. Then prefold this folding line to the centerline.

Step 31:
Repeat steps 2 to 6.
The left line is about 1 cm off the edge.

Step 32:
Fold the lower part in half two limes, fold to the prefolded line indicated by the pink arrows.

Step 33:
Glue both ends together.
Then repeat steps 9 to 11

Step 35:
The papers for the small box are made by glueing 2 squares together. Prefold in half over the purple line

Step 34:
And the medium size box is also done.....

Step 36:
Prefold to the centerline

Step 37:
Repeat steps 2 to 6
The left line is 2 cm off the edge

Step 38:
Fold the edge to the centerline

Step 39:
Glue both ends together.

Step 44:
Fold over the purple line, about 1 cm off the edge.

Step 41:
Done.....

Step 40:
Fold all eight spots / corners downwards.

Step 42:
Prefold in half. Then prefold the upper edge to the centerline.

Step 43:
Repeat steps 2 to 6.
The left line is 1 cm off the edge

Step 45:
Fold the part below the upper prefolded line in half two times

Step 46:
Glue both ends together.
And repeat steps 9 to 11