The dry pieces of woodshould be the legs, fitting in to the main seat piece of green wood (freshly cut piece of wood). The idea is that the green wood will shrink and further tighten itself to the pieces of dried wood.
Holes are made in the green wood, and the dry leg pieces are inserted into it.
The seat of green wood is a cut cross section of a log, and the legs are inserted into one side. You can use three or four legs, although three should be the easiest.
I made this tiny stool this morning. I don't know if it'll fit this Badge Bit, but it was what inspired me to make a little seat for my kids' fairies. The legs are dry holly wood, and the seat is green Big Leaf Maple wood.