Print on the heaviest paper or card stock that your printer will allow.
Cut around the outline of the box
Following the hape of the boxes.
Fold on the lines where the four sides of the box meet the plain white parts that have the flaps or the box cover.
If you have never made one of these I suggest you print one on paper and use it as practice till you get the hang of it. It's easy if you try.
Glue if necessary.