Ok, in scibors simplified technique you use fimo, or sculpy, basically some sort of bakable clay (not air curing), then after you imprinted your pattern as he shows, you would bake it following the instructions on the packaging (of the sculpy/fimo). After this you would then lubricate your mold (the baked fimo) and press in some greenstuff. Wait for a while, probably 1-3 hours depending on your mix, and remove it being careful not to mangle it, and shape it as desired (scibor shows it resting on a cork to curve it), before letting it cure completely. Hope I\'ve helped clear things up for you.
P.S. Sculpy and Fimo can be bought from almost any craft or art store, maybe even some of the larger department stores as well. It\'s not terribly expensive either. I personally prefer Fimo, but that may just be me.