I would not suggest using that. I did use a video to help learn and still use it on occasion just so I don't feel like I am doing it alone. The difference is the video I use is by the person GM William Cheung chose to serve as the North American Liaison for the World Wing Chun Kung Fu Association. This is what my Sifu teaches but the video does a decent enough break down for what I think your purposes are. In a different thread you said you were considering it, not so much as to learn the proper techniques (the Sil Lum Tao is basically the foundation of all WC techniques) for WC fighting but as meditation. I can't speak to the app in question but this DVD is decent for that purpose.
SIL LUM TAO REVEALED
If you wanted to actually build that foundation to move onto WC fighting, I would side with Flying Crane. In the beginning you will have issues if an instructor isn't there to catch you because their are seemingly little things in the structure of the Mah, proper placement of the arms, etc.