First, if you can get a copy of Kathy's DVD do it. It's a fantastic piece.
A furled leader is made in much the same way as rope, by twisting strands if strick togther. Tapering is done by the number of strands at each end. Basically it is built on two legs, each leg will consist of interlocked loops, one end will have 5 looops the midde 4 and the other end 3. This makes a taper of 10 - 8 - 6. Perfect for 3-5wt lines.
I build most of mine 5' then use 24" of 4x and then another length of what I need to fish with.
Pete