Step 1: First of all, just go to the download page of the app and click the app from there.
Step 2: Now, You got the popup Massage of unknown Resources.
Step 3: just click on enable in the popup Massage of unknown Resources. When your app is installed may it takes time for few seconds
Step 4: Now, after the installation of the app, just go to the menu bar of your device click on the app, and then choose your interest and watch your favorite content.