They do list out some steps on the site and also have this safety precaution:

Safety Note: do not throw anything into the fire container. Your fuel will splash out and spread fire. A damp piece of plywood can be used to suffocate this flame if needed. The entire metal container and contents will be extremely hot. Let it sit and cool before anyone touches it.

Special thanks to the folks at Unallocated Space for inspiring this build with their fire tornado video.

Once again don’t try this!

thanks to makezine for the great info and pic