Using the app is very simple. Just search by channel's name and select it from the list. In addition to the total number of views, the number of posted videos, total of likes, total of dislikes and total of subscribers are also displayed. You can also highlight channels.
The total number of views on channel's screen is updated every 5 seconds. There are several factors that influence the accuracy of views count, such as: validation of visualizations and delay in receiving data. Therefore, the total number of views displayed in this app may be not match the real number of views. It's impossible get a precise number, only YouTube can do that.
The app also has a widget, which can be used to track the views of highlighted channel more easily. This widget can be positioned on the smartphone's screen and it will update the number of views of the selected channel every 30 minutes.
It is important to clarify that all the information used by the application is public and made available by Youtube itself.
I hope this app helps you grow your channel. Good luck!