I just made my first batches. I didn't really know exactly how when I started but had the general idea.
I used some old jeans, cut them up and stuffed into a little Altoid's gum tin. I also did a larger batch in an old tea tin.
After about 30 minutes of horrible smelling smoke I took the tins off the fire (charcoal).
After it cooled I checked the tin; the cloth was totally black and weighed a fration of its original weight. I tried my Sparklite on it. The first tiny spark caught the edge of the cloth and it started glowing into a large ember right away.
This was a really cool experiment. I suggest you try it.