Paper Size: Select Letter, Legal, A3, A4, or A5 based on the size of the paper in your printer.

Number of Fins: Select the number of fins (three to eight) that will be on your rocket.

Include Launch Lug: Select "Y" (for "Yes") to include a guide line for placing the launch lug on your rocket.

Body Tube: Select the body tube you are using or "Other" to manually enter the diameter.

Body Tube Diameter: If you selected "Other" for the Body Tube, then enter the outside diameter of the body tube. Be sure to select the proper units in the next field.

Units: Select the units for the Body Tube Diameter ("inches," "millimeters," or "centimeters").

After you click the Submit button, the guide will be downloaded as a PDF file. When printing the guide, make sure to select the "Actual Size" setting. The outer square in the lower right should be one-inch wide and one-inch high. The inner square should be 20mm high and 20mm wide.