I've worn this style a couple of times.  Its a modern version of a pompadour.

Take a 2 inch section from crown to front.  Gently backcomb-I guess they're calling this Back Lacing since its not as intense as ratting the hair, and then smooth the top back.  Use a gentle hold hairspray.  Gather the ends at the back of your head and clip with a small claw, pushing the hair forward to create the pouf.

Add the rest of the hair to make a ponytail, leaving the clip in your hair.

I was very gentle and when I took it out I combed it with a silicone comb and had no knots.  The clip is the key, and a bit of hairspray.

do you mean a poofy bun? like this

for this you just put your hair in a pony tail, highish up, put hair forward and place a hair comb where its cobed over, then comb hair over the hair comb and tuck ends in and clip down!