Easy way to do it...
Rev gas with right foot.
Hold clutch in with left foot.
Dump clutch, quickly move left foot to brake.
Hold left foot on brake as needed.
Watch my example
here in my old Z28.
Note: this is the first time I'd ever tried it a burnout in a manual car... so my foot work was a little slow, that's why the car lurches... plus I didn't figure it'd start to move that quickly given the wheelspin...