This is a guide to help apply the tail fins to paper and tape rockets used on 1/2" NPT launch tubes. Our free to download template can be found here: https://www.airrocketworks.com/wp/standard-template/ The NASA templates can be found here: https://www.airrocketworks.com/wp/nasa-kennedy-space-center-templates/ There are two ways to use this fin guide, use one side of the guide for straight fins, or use the other side for 5° angled fins to make the rocket spin. Start by building the rocket body tube, then load the PVC mandrel into the center of the guide. Slide the body tube down to a comfortable working height. Fold the fins, and apply tape to one side of each fin. Tuck the flap without tape between the body and the fin guide. Once aligned, smooth down the tape on the other flap. Once all three are taped, remove the mandrel and rocket, and apply tape on the other side of the fin to fully secure it. Note that the rocket shown in the picture has multiple launches, which explains the somewhat crumpled nosecone... I should really get a better picture.