Step 2. Go to your device settings and scroll down to security;
Step 3. In the security section, scroll down and look for "Unknown Sources" and click the checkbox. This is because Android devices don't allow manual installation of apps without the user allowing this feature in the settings; you can always turn it off by un-checking the box if you are done;
Step 4.Go to your download History and open the downloaded Spotify App;
Step 5.Click on "Next" button and then tag "Install" to install the Spotify app;
That's it, Spotify music app has been successfully installed in your android device.
You can try to download Spotify App from official source from ( Google Play | Amazon )