All the apps you download will appear automatically together with other apps.
There are 2 methods to open the application drawer.
1st, the conventional from older version.
To access them just go to the Home screen and then touch Apps. Swipe left or right to cycle between the pages.
Some devices, such as the Galaxy S4 and Note II, have a Downloads icon in the top-right of the screen. Touch this to see only the apps you have downloaded (not the apps that came pre-installed with your device).
2nd, the newly applied method on Galaxy S8/S8+
With Galaxy S8/S8+, you can access your application drawer by swiping app or swiping down from the home screen.