you pack the substrate, and then cut the foil into sqauresu pack squares into the jar, but dont compact it in....justy have the foil come right up to the mix, and flat against jar sides....so it makes a little pond thype thing. fill this pond with dry vermiculite....put the cover on. Four jars with ramsey, 4 without, 4 are almost 100% colonized and look perfect, 4 are about 80 with some questionable spots....so it seems to work well for me, but other ppl have said its a waste...my tek recomends it.....sorry im not too good at wording how to do it, some teks explain the procedure fully