Help Files problem

[Vehyr]

I want to install apps from applications ( no play store ) , and it's saying me " X application is not installed " , how to resolve the problem ??

 

[SavageRobot]

You mean 3rd party app stores? Wouldn't recommend using anything other than Play Store or Amazon, but if you are wanting to install from elsewhere you have to enable unknown sources. I don't really understand what error you are saying you are getting but that would be the first thing to check...Settings>Security>toggle "Unknown Sources" to allow.