you can also read this in dutch:
Step 1: Get a metal container.
height about 50cm
diameter about 30 cm
depending on how big space you want to heat.
I have also tried various metal rubish-bins.
it doesn't matter if the metal is thin. that way it heats up the space much faster.
don't use anything aluminium. it will catch fire when tempreture gets high enough for spontanious combustion, melting or realy aggressive burning with hot sparks flying about.
Step 2: Get teapot and saucepanlid
snip the edges then bend and bang inside so you've got a smooth edge with no sharp bits and hopefully your saucepanlid will fit nice and snug.
Step 3: Burn paint off
Step 4: Smoke valve (optional, but recommended)
then draw a hole for the flue right near the top of the drum. cut out in segments and bend all the sharp bits inside so they lay flat.
a trick to keep the heat in is an adjustable baffle in the chimney, just squewer a baked bean tin lid with a tent peg inside the chimney.
Step 5: Close bottom and fill 1/3 with clay.
Step 6: Make holes to control fire
you can just drill holes and have big bolts to seal up holes when you want the burner to slow down.
You can also make a slide.