There are 5 homescreens that you can swipe to the right or left.
You can press and hold a widget and delete it by moving it to the x that will appear upper left, or move the widget to another homescreen by holding it to the right or left while the screens scroll underneath.
Once you have the screen cleared, go to the apps you want, long press will bring them to the homescreen. Dropping one app on another will make a folder. Swiping through the apps directory will get to widgets that can be installed the same way.(in case you deleted and want them back)
If you have somehow changed the wallpaper to display all your photos, long pressing a non-app/widget area will allow you to change the background wallpaper to something less confusing.
My library and my movies are widgets.