Apps on my Note 3

[Dirhael]

I know this isn't something about computer stuff, but I figured that some of you might know anyway. When I try to download something from another source than Google play store (on my galaxy note 3), It doesn't work... I've checked the option in security>settings>Unknown sources, but it still doesn't work... I get to all the agreements and such, but the Install button doesn't work.. ;-; Do you guys know anything about this problem, because it has been bugging me for quite a bit now.

 

[Dirhael]

Anyone?