Provide advice on how to accomplish the following goal. Give ONLY the advice, no other words or explanation.
For example:

Answer: <advice, as short as possible; a single sentence!>.

Goal: How do I cut off the top of the box ?
Draw with a pencil a line parallel to the top of the box and 3 inches lower than the top of the box. Then, cut on  the line with a band saw.
Use a box cutter to score and snap off the top flaps.