The app essentially advertises the cue and the coaching but gives you a little more detail about how they teach their method.
In a nut shell you align yourself such that you are percieving the shot line properly, put your foot on the line (you have step in a bit more if you are equally eyed), grip hand should be on the shot line and without movingly he grip hand pivot the bridge hand on to the shot line and drop straight down. That's how I remember it off hand anyway. A bit more to it than that. You also get a bunch of videos that outline some practice routines.
You get a few videos explaining the process. Never tried the cue though,