We'll start with the 3/4" diameter PVC pipe. To begin construction, cut your PVC into three different lengths with a handsaw.

You'll need one 12-inch piece, one 9-inch piece, and one 6-inch piece.

Next, fit your 12-inch piece with your two elbow joints, one facing to the side and one facing up.

Attach your 6-inch piece to the joint facing up, and the 9-inch piece to the joint facing to the side.

Now we move on to the plastic bottle. Put your coupler on the mouth of the bottle and duct tape into place.

Now that your bottle has a coupler, you can easily fit it onto the 9-inch PVC, laying flat on the ground.

Let's move on to the rockets! You'll probably want to make several before you start to play with your stomp rocket setup. For the first step here, you'll need your paper or card stock, PVC pipe, and duct tape.

Roll the card stock around the pipe and tape into place, creating a tube. (This way you know your rocket will fit on your launcher.)

Duct tape the end of your tube shut, making it as airtight as you can.

With more tape, tape the tube completely shut, sealing off any air leaks.

Decorate your rocket with tape however you want!

To launch, fit your rocket on the open end of your launcher, and stomp down on the bottle! The air in the bottle forces the rocket skyward! Three... two... one... blastoff! (A word of caution: never fire your rockets at anyone on purpose, and be sure your launch area is clear before stomping!)