Adam's Paper Rockets

You'll want the instructions and one or more variant of template:

The templates are all the same except for different fin designs, so print whichever you want!

You need:

Printed instructions (on normal paper or whatever)
Printed template (ideally on cardstock e.g. 90gsm, but paper can work too)
Plain A4/letter paper to roll into body tube
Scissors and tape for everyone
Estes A8-3 single-use rocket motors, available in 3-packs and 24-packs (part number D-ES1781), e.g. from rapidonline.com or modelrockets.co.uk or elitemodelsonline.co.uk
Hot glue gun and glue for it
Enough space to launch the rockets, recommend 20m clear radius from launch pad
Some sort of ignition system for the motors, can be purchased commercially or home made, just needs to put ~1A through the e-matches that come with the motors for a couple of seconds
Some sort of launch rail: at least, a thin metal rod the rockets can slide up (around 60cm-1m long) and a metal plate to go below them to avoid burning the ground
Let me know anything I forgot...

Once the rockets are constructed as per the instructions:

Using hot glue gun, smear some hot glue over motor and insert into bottom of rocket, making sure it is the right way around: propellant down, empty space up.
Check launch lugs fit on rail and slide freely
Let me know anything I forgot...